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P R E F A C E

Part G of the manual covers the design of storm drainsonly. It presents the design criteria, standards, policies, andprocedures to the new engineer and provides a reference source forthe experienced designer. Other office or processing operationsrelated to storm drain design are covered in other parts of themanual.

The design of storm drains by City forces for the LosAngeles County Flood Control District or the State Division ofHighways is not included in this manual.

June , 1973GENERAL OUTLINE

G 000 INTRODUCTIONLiability and Responsibility, Project Types and Agency Jurisdictions, Capital ImprovementProjects, Assessment Projects, Private Development Projects, Easements Watercourses,Drainage Complaints.

G 100 GENERAL DESIGNPolicy, Design Practices, Types of Drainage Systems, Excavation and Backfill, Grading andErosion Control, Soil Mechanics Nomenclature, Geological Nomenclature, Preliminary Study,Hydraulic Laboratory.

G 200 HYDROLOGIC DESIGNRainfall Frequencies from Rain Gages, General Criteria, Surface Flow, Peak Rate Method,Method of Summing Hydrographs, Method for Undeveloped Mountain Areas Hydrology forReservoirs.

G 300 PRESSURE FLOW DESIGNDesign Procedure, Pre-Design Data, Hydrology and Alignment, Main Line Hydraulics, CatchBasin Design, Preliminary Plans, Construction Controls, Final Plans, Design Check Prior toAdvertising for Bids.

G 400 FREE WATER SURFACE DESIGNGeometric Design, Hydraulic Design, High Velocity Design-Sample Project.

G 500 STORAGE BASIN AND PUMPING PLANT DESIGNBasic Design Data, Design of Storage Plus Gravity Outflow, Design of Storage Plus Pumping.

G 600 STORM DRAIN STRUCTURESConduits, Standard Structures, Special Structures, Appurtenant Construction.

G 700 PLAN PREPARATIONStandards, Title Sheet, Plan and Profile Sheets, Detail Sheets, Plan Processing andConstruction.

G 800 CONSTRUCTIONResponsibilities and Relationships, Design Changes Prior to Contract, Duties DuringConstruction, Change Orders, Final Inspection.

G 900 CULVERT DESIGN Criteria, Culvert Operations, Hydraulic Design, Alignment and Structures.

INDEX

APPENDICESA. Hydraulic Properties of Streets-Office Standard No. 94B. Design Charts for Catch Basin Openings-Office Standard No. 108C. Hydraulic Analysis of Junctions-Office Standard No. 115D. Hydraulic Properties of Pipe, Boxes, and Rectangular Channels-Office Standards Nos. 116

and 117E. Maximum Allowable Flow in Streets - Office Standard No. 118

June , 1973TABLE OF CONTENTS

INTRODUCTION ( G 000 )

SECTION NO. SUBJECT DATE

G 010 LIABILITY AND RESPONSIBILITY June, 1968G 011 Definitions June, 1973G 012 Public Liability June, 1968G 012.1 Laws and definitions "G 012.2 Rights and obligations "G 012.21 Private Property June, 1969G 012.22 Municipality June, 1968G 012.3 Practical Design Applications June, 1969G 012.4 Excerpts from Court Decisions and Other Authorities June, 1968G 012.41 Distinction between Surface Waters and Food Waters "G 012.42 Rights and Obligations Respecting Surface Waters "G 012.421 Private Persons Respecting Surface Waters June, 1969G 012.422 Cities Respecting Surface Waters June, 1973G 012.43 Floods Attributable to Flood Waters June, 1969G 012.5 Personal Conduct June, 1968G 013 Bureau Responsibility June, 1973G 013.1 District Responsibility "G 013.2 Storm Drain Design Drain Responsibility June, 1968G. 013.3 Personal Responsibility "

G 020 PROJECT TYPES AND AGENCY JURISDICTION "G 021 Corps of Engineers June, 1969G 022 State Division of Highways "G 023 Los Angeles County Flood Control District "G 024 City of Los Angeles "G 025 Other Agencies June, 1968G 030 CAPITAL IMPROVEMENT PROJECTS June, 1969G 031 Financing June, 1968G 031.1 State Gas Tax Fund June, 1973G 031.2 County Gas Tax Fund June, 1969G 031.3 Permanent Improvement Fund June, 1968G 031.4 Other Funds June, 1969G 032 Preparation of CIP Request "G 033 Cost Estimate Classification June, 1968G 040 ASSESSMENT PROJECTS June, 1969G 041 Preliminary Procedure "G 042 Design Considerations June, 1968G 043 Drainage Assessment District June, 1969

TABLE OF CONTENTS

SECTION NO. SUBJECT DATE

G 050 PRIVATE DEVELOPMENT PROJECTS June, 1969G 051 Subdivisions June, 1973G 051.1 Drainage Policy for Approval of Subdivisions June, 1969G 051.2 Definitions "G 051.3 Causes for Withholding Approval "G 051.4 Means for Providing Adequate Facilities "G 051.5 Additional Requirements "G 051.6 Maintenance of Basins "G 051.7 Submittals for Approval June, 1968G 051.71 Tract Map June, 1969G 051.72 Grading Plan "G 051.73 Storm Drain Plans "G 051.74 Erosion Control Plans "G 051.8 Flood Hazard Report "G 052 Lot Splits and Single Lots June, 1968G 052.1 Drainage Control June, 1969G 052.2 Watercourse Considerations "G 052.3 Inundation Report "G 060 EASEMENTS June, 1968

G 061 Definition June, 1969G 062 Policy "G 063 Types of Easements "G 063.1 Temporary Easements "G 063.2 Slope Easements "G 063.3 Combined Easements "G 063.4 Future Easement "G 063.5 Rights of Entry "G 064 Work in a Drainage Easement June, 1973G 065 Common Right of Way Terms June, 1969G 070 WATERCOURSES "G 080 DRAINAGE COMPLAINTS "

LIST OF FIGURES

NUMBER TITLE DATEG 023 LACFCD Comprehensive Plan June, 1968G 052.3 Inundation Report "G 064 Application to do Work on City Easement June, 1969G O64A to I Waiver of Damages Agreement and Modifications "G 064J & K Instructions for Processing Waiver of Damages June, 1973G 070 Application-permit to Work in Natural Watercourse "G 080 Drainage Complaint Report "

June , 1973

Bureau of EngineeringManual - Part G STORM DRAIN DESIGN

G 000June, 1973

G 000 INTRODUCTION

To provide the City of Los Angeles with stormwater runoff facilities has been a constant, costly,and complex endeavor. The City is surrounded bysharply rising mountains which create heavy runoffinto the flat plains below extending some 30 milesto the ocean. This factor, coupled with the highintensities of rainfall which occur betweenNovember and April, makes the Los Angeles areaone of the most vulnerable to flooding in thecountry for density of population.

The City of Los Angeles is relatively young incomparison with many large cities of comparablesize. Most of its growth has taken place during thepast 50 years, during which many changes ineconomic factors and engineering have occurred.Consequently, storm drains and other drainagefacilities deemed hydraulically adequate oreconomically sufficient in the early l900’s have

proved inadequate in recent years due to changes inaccepted methods of evaluating storm runoff.

At present, the greatest portion of the City’s 460square miles has been subdivided and developed, andevery effort has been made to provide adequatedrainage facilities. Approximately 1000 miles of City-owned storm drains have been constructed. exclusiveof those constructed and maintained by the U.S. ArmyCorps of Engineers, the Los Angeles County FloodControl District, the State Department ofTransportation, and the Soil Conservation Service ofthe U.S. Department of Agriculture. Nevertheless, thephenomenal and unanticipated growth of the City hasresulted in many drainage deficiencies.

These existing problems, along with those whichwill result from the future development of the City,form the challenge which the storm drain designengineer must meet.

G 010 LIABILITY AND RESPONSIBILITY

G 011 DEFINITIONSRefer also to all definitions in Section 1-2 of

the Standard Specifications for Public WorksConstruction (Latest Edition) with supplements.

1. Watershed: A drainage area bounded onthree sides by ridges where flow by gravity of allrunoff within the area drains ultimately to aparticular watercourse or valley street which outletson the fourth side. The fourth side is establishedwhen its flow joins the flow of an adjacentwatershed.

2. River: A large stream of water whichserves as the natural drainage channel for awatershed of considerable area.

3. Watercourse: A natural stream of waterflowing in a particular direction in a definitechannel having a bed and banks. It need not flowcontinually, nor is it restricted as to propertyownership.

4. Runoff: The amount of rainfall (less lossesfrom infiltration, evaporation, transpiration,interception, and storage) which flows naturally onthe earth’s surface.

5. Storm Drain System: A combination of alldrainage facilities within a watershed, including

natural watercourses and conduits, to convey surfacerunoff from its most remote location to the watershedoutlet.

6. Trunk Line: The major collector conduit of astorm drain system. Trunk lines accept flows fromsmaller contributing storm drains and generally outletinto major or secondary watercourses (see Section G020).

7. Lateral: A storm drain conduit which outletsinto a trunk line when considered as a part of a stormdrain system. In terms of a storm drain project, alateral is a conduit which outlets into the main line.

8. Main Line: The principal conduit of a stormdrain project. A main line collects flow from lateralsand catch basin connections.

9. Storm Drain Project: Storm drain conduitconstructed under a single contract. This does notinclude catch basin connections or culverts whenconstructed alone.

10. Catch Basin Connection: A storm drainconduit which conveys surface runoff froma catch basin or catch basins to atrunk line, a main line, or a lateral.


G 012June, 1969

G 012 PUBLIC LIABILITY

Almost every aspect of municipal action ondrainage and flood control work may have seriouslegal complications. Therefore, the design engineermust be able to recognize liability and avoidsituations in which liability would be incurred.

This section summarizes some general rulesapplicable to storm drain design. These rules areonly a guide, and the designer should remember thatthey do not necessarily represent the controllinglaws of California The interpretation of state laws isalways the responsibility of the City Attorney’soffice, which will furnish appropriate advice uponrequest.

G 012.1 Laws and DefinitionsPublic Liability Act: This act provides that a

local agency is liable for injuries to persons orproperty resulting from the dangerous or defectivecondition of public property, provided the personauthorized to remedy the condition had knowledgeof the condition and failed to remedy it or takenecessary action to protect the public within areasonable length of time.

State Constitution: This constitution providesthat a local agency shall not take or damageproperty for a public purpose without paying fullcompensation therefor.

Diversion: An act of man which alters thedirection of surface water flow from one drainagewatershed to another.

Negligence: The failure to perform an actwhich a prudent and reasonable person would beexpected to perform, or the performance of an actthat such a person would not be expected toperform. Such expectations are guided by thoseconsiderations that ordinarily regulate the conductof human affairs.

G 012.2 Rights and Obligations: Inherent withrights are obligations. Both the private propertyowner and the City have rights with respect to theuse of property, and obligations to each other. Thissection is concerned only with those rights andobligations pertaining to surface waters anddrainage.

G 012.21 Private Property: A property owner hasthe right to develop his land normally, provided hedoes not injure or damage any person or property,and provided he complies with all applicable legalregulations.

Riparian Water Rights: The owner of the landbordering upon a river has no absolute ownership ofthe waters, but has a right, in common with others, tothe reasonable use of waters flowing past his land.

Doctrines of Surface Water Law:First, the common enemy doctrine. Under thisdoctrine, each owner has the unqualified right to fendoff surface waters without regard to the upper ownersor other owners.

Second, the civil law rule. Under this rule, thelower owner must accept upper water in its naturalcondition, but the upper owner has no right to alter thenatural system of drainage.

Third, the rule of reasonable use. The rights of theparties are determined by assessment of all the factors.

The Supreme Court adopted for California the civilrule subject to the rule of reasonable use. The courtsaid: “The issue of reasonableness becomes a questionof fact to be determined in each case upon aconsideration of all relevant circumstances, includingsuch factors as the amount of harm caused, theforeseeability of the harm which results, the purposeor motive with which the possessor acted, and allother relevant factors.”

The court concluded that if both the upper andlower owner act in a reasonable manner, then the civillaw applies; namely, that the upper owner has to bearthe costs of diversion to the lower owner. Otherwise,if one side acted more reasonably than the other, thenthe burden would be borne by the one who acted lessreasonably.

(For more detailed information, refer to SubsectionG 012.4)

G 012.22 Municipality:Police Power is the power of a local agency to

enact and enforce laws within constitutional limits topromote order, safety, health, morality, and thegeneral welfare of society. This power is properlyexercised by the City in making public improvements,provided ---

a. The taking or damaging of property isessential to the public welfare;

b. Reasonable care and diligence are used inproceeding with the improvement;

c. No needless injury is inflicted upon privateproperty; and,


G 012.3June, 1969

d. The City’s action does not constitute atrespass upon private property.

Eminent Domain is the right of a governmentalagency to acquire property for the development ofprojects of benefit to the public as a whole. Justcompensation must be paid for the property.

The City of Los Angeles has the duty to invokeits rights for the protection of the public and thebetterment of the community.

G 012.3 Practical Design Applications:Below is a list of principles which the engineer mustconsider in designing storm drains.

a. Do not divert surface waters from oneproperty to another over which they would notnaturally flow.

b. Do not gather waters by artificial meansand discharge them onto lower property in greatervolume or concentration than they would naturallybe discharged (except that the volume may beincreased by urbanization or by development of theupper property-see Subsection G 012.43, c).

c. Do not construct ditches or other artificialstructures to drain waters which have accumulatednaturally in ponds and depressions onto lowerproperty owned by another person.

d. Do not direct surface waters which havebeen improperly diverted from still higher propertyonto lower property.

e. Do not concentrate surface waters into asingle channel, instead of two or more, and thendischarge the channel onto lower property.

f. Do not obstruct the flow of surface watersfrom higher property that naturally drain across oronto lower property.

g. Do not construct public drainage systemson private property; easements for drainage andconstruction purposes are to be acquired by the Cityprior to construction.

G 012.4 Excerpts from Court Decisions andOther Authorities: Relating to Watercourses,Surface Waters, and Flood Waters as they mayaffect, or be affected by, the Design, Construction,and Operation of Storm Drains and other Drainageand Flood Control Works, Streets, Subdivisions,and other Municipal Improvements-Prepared byFerdinand P. Palla, City Attorney of the City of SanJose, California, and Presented in a Paper Titled “Responsibility of Public Works Officials

for Control of Flood Hazards in Cities,” to the Public-Works Officers’ Department Annual Conference atLos Angeles, California, October 25, 1960.

A summary of the text of the subject paperincludes:

1. Distinction Between Surface Waters andFlood Waters

2. Rights and Obligations Respecting SurfaceWaters

3. Floods Attributable to Flood Waters

As cities expand and develop, and former rural oragricultural areas become urbanized, cities, andparticularly their public works officials, are constantlyconfronted with serious drainage problems which, ifleft unsolved, might result in extensive flood damage.Waters which formerly percolated into the groundcannot penetrate the rooftops, pavements, and otherimprovements in new subdivisions. The natural flowof surface waters is altered, and watercourses oftenbecome inadequate to handle increased runoff ofsurface waters. To what extent do cities and theirpublic works officials have a responsibility to preventsuch damage? An attempt is made in this paper to givesome of the answers. However, the legal answersdepend so much on the circumstances of a particularsituation that, at best, only the general rules can begiven. Designers seeking answers covering specificsituations should always consult with their cityattorney, since what might appear to be a slightchange in circumstances might well render a generalrule of law in applicable.

G 012.41 Distinction Between Surface Watersant Flood Waters: The rules of law governingliability for flood damage caused by “surface waters”differ from the rules applicable to flood damagecaused by “flood waters.” In this paper, “surfacewater” damages and “flood water” damages aretherefore discussed separately How do the courtsdistinguish the two types of waters?

a. “Surface Waters” Defined. “Surface Waters,”often better referred to as “diffused surface waters,”have been defined by the California Supreme Court asfollows:

“Surface waters are those falling upon, arisingfrom, and naturally spreading over lands produced byrainfall, melting snow, or springs Theycontinue to be surface waters until, in


G 012.41June, 1969

obedience to the laws of gravity, they percolatethrough the ground or flow vagrantly over thesurface of the land into well definedwatercourses or streams . . . After they havebeen gathered into a natural channel, however,they become stream waters . . . Everett v.Davis, 18 Cal. 2d 389, 115 Pac. 2d 821 (1941).

Surface waters never originate in overflow ofstreams, such overflows being commonly referredto as “flood waters” rather than as surface waters.The essential distinction between these two classesof waters is that surface waters have not yet becomepart of a watercourse, whereas flood waters wereonce a part of a watercourse, but have broken awaytherefrom. Horton v. Goodenough, 184 Cal. 451,194 Pac. 34 (1920).

b. “Flood Waters” Defined. “Flood Waters” arewaters which were once part of a stream but haveescaped therefrom and overflowed onto adjacentterritory. The California Supreme Court, inconsidering the matter, has stated:

“Implicit in the definition of flood waters is theelement of abnormality, they are flood watersbecause of their escape from the usual channelsunder conditions which do not ordinarily occur.

“As flood waters are those which break awayfrom a stream under conditions which do notusually occur, they can never be the flow of astream at the end of its channel.”

Flood waters retain their identity as such whileflowing wild over the country. Mogle v. Moore, 16Cal. 2d 1, 9, 104 Pac. 2d 785. They do not includehigh waters flowing in the natural channel of astream, since in such case they haven’t escapedfrom the stream. Costello v. Bowen, 80 Cal. App. 2d621, 182 Pac. 2d 380.

Since waters cannot be “flood waters” unlessthey were once a part of a stream or watercourse,courts occasionally must determine what is a streamor watercourse. In 1902, in the case of Sanguinetti v.Pock, 136 Cal. 466, 69 Pac. 98, the CaliforniaSupreme Court defined a watercourse as follows:

“There must be a stream, usually flowing in aparticular direction, though it need not flowcontinually. It may sometimes be dry. It must flowin a definite channel, having a bed or banks, andusually discharge itself into some

other stream or body of water. It must be somethingmore than a mere surface drainage over the entireface of the tract of land, occasioned by unusualfreshets or other extraordinary causes. It does notinclude the water flowing in the hollows or ravinesin land, which is mere surface water from rain ormelting snow (i.e., snow lying and melting on theland), and is discharged through them from a higherto a lower level, but which at other times aredestitute of water. . .”

In 1947, in the case of Costello v. Bowen, 80 Cal.App. 2d 621, 182 Pac. 2d 615, the CaliforniaAppellate Court further defined a watercourse asfollows:

“In general terms it has been said to consist of arunning stream of water following a regular course orchannel and possessing a bed and banks. . .

“It is the channel through which the water of aparticular district or watershed usually or periodicallyflows. While it is ordinarily defined as a stream,containing a definite bed, banks and channel, whichflows into some other river, stream, lake or the sea,none of those characteristics is an absolute fixedfactor. A watercourse may exist even though it servesas a mere channel by means of which a particularwatershed is drained, and although it may be dry incertain seasons, or despite the fact that it may notempty into any other river, stream, lake or body ofwater, but, on the contrary, even though it terminatesin some sandy basin where it disappears from sight . . .The question of the existence of a watercourse is oftenone of fact to be determined by a jury or the court. Ifthe evidence in that regard is conflicting, thedetermination of the trial court will not be disturbed onappeal . . .”

A slough that carries no water except in time offlood and that is simply a conduit by which occasionalflood waters of a nearby river escape into adjoininglowlands has been held to be not a watercourse. Lambv. Reclamation District, 73 Cal. 125, 14 Pac. 625(1887). Nor does a stream include water deposited“during time of storm which immediately runs awayand leaves in its course a mere stretch of sand androck.” San Pedro L.A. and S.L. RR v. Simons BrickCo., 45 Cal. App. 57, 186 Pac. 62 (1919).It has been said that a stream

Bureau of EngineeringManual – Part G STORM DRAIN DESIGN

G 012.42June, 1969

meets the requirements of a watercourse if it flowswhen streams in the general region are accustomedto flow. McManus v. Otis, 61 Cal. App. 2d 432, 143Pac. 2d 380.

G 012.42 Rights and Obligations RespectingSurface Waters: Article 1, Section 14, of theConstitution of the State of California provides thata city shall not take or damage property for a publicpurpose without paying compensation therefor. Inmost suits against cities for flood damages, it is thisconstitutional provision which is cited as the legalbasis for the action. It is significant that, unlike asimilar provision in the United States Constitutionwhich refers only to taking of property, theCalifornia Constitution also prohibits the damagingof property for a public purpose, unless fullcompensation is paid therefor. There are twodefenses which a city often seeks to make in suchsuits. One is that the injury is such that a privateperson would not have been liable if he had causedit, and that therefore the city should not be liable. Inthis respect, the California courts have held that aplaintiff, to recover under the above constitutionalprovision, must prove that the injury is one whichwould give rise to a cause of action on the part ofthe plaintiff if it were inflicted by a private person.O’Hara v. Los Angeles County Flood ControlDistrict, 19 Cal. 2d 61, 119 P. 2d 23 (1941). Theother possible defense is that the injury was a resultof the reasonable exercise by the city of its “policepowers.” In this respect, the California courts haveheld that the taking or damaging of propertyresulting from the reasonable exercise by a city ofits police powers is an exception from theapplicability of the above constitutional provision,and not compensible. Lampe v. City and County ofSan Francisco, 124 Cal. 546, 57 Pac. 461. It isessential, therefore, in determining the legal duties,responsibilities and liabilities of cities and publicworks officials with respect to surface waters toconsider (1) the rights, duties, and liabilities ofprivate persons with respect to surface waters, and(2) the nature and scope of a city’s “police power.”

G 012.421 Rights and Obligations of PrivatePersons with Respect to Surface Waters:

1. General Rule. It is well established that aprivate landowner must bear the burden ofreceiving upon his and the surface water naturally

falling upon land above it and naturally flowing to ittherefrom, and he has a corresponding right to havethe surface water naturally falling upon his land ornaturally coming upon it, flow freely therefrom uponadjoining lower land, as it would flow under naturalconditions. Heier v. Krull, 160 Cal. 441, 444, 117Pac. 530 (1911); Andrew Jergens Co. v. Los Angeles,103 Cal. App. 2d 232, 235, 229 Pac. 2d 475 (1951).

2. Restrictions on Upper Landowners. An upperprivate landowner has been held to have no right todivert surface waters from his land or.to lands ofanother over which they would not naturally flow,Wood v. Moulton, 146 Cal. 317, 80 Pac. 92 (1905);nor to gather such waters on his land by artificialmeans and discharge them onto lower land in greatervolume or in different manner than they wouldnaturally be it onto discharged, San Gabriel ValleyCountry Club v. County of Los Angeles, 182 Cal. 392,398, 188 Pac. 554 (1920); nor to change the flow ofwater to the injury of a lower owner, Shaw v.Sebastapol, 159 Cal. 623, 624, 115 Pac. 213 (1911);nor to construct ditches or other artificial structuresand thereby turn waters which have naturallyaccumulated in ponds and depressions on his landonto lands of a lower owner, Galbreath v. Hopkins,159 Cal. 297, 301, 113 Pac. 174 (1911); nor to collectsurface waters into a single channel, instead of three,and discharge it on a lower owner’s land, Humphreysv. Moulton, 1 Cal. App. 257, 81 Pac. 1085 (1905). Noteven when surface waters have been improperly .diverted to his lands from still higher lands may anupper proprietor direct such waters to the lands of alower owner. Allen v. Stowell, 145 Cal. 666.Thompson v. La Fetra, 180 Cal. 771. Such acts havebeen called an invasion and injury to property and anuisance per se. (Galbreath v. Hopkins, supra.) But heis not responsible for a concentration of flow causedby unlawful diversion above him, before the waterreaches his land, and he need not intercept such flow.Mathews v. Kinsell, 41 Cal. 512. Also the above doesnot mean he cannot build ditches or drains on his land:he may, provided his neighbor is not thereby injured.Galbreath v. Hopkins, 159 Cal. 297.

3. Restrictions on Lower Landowners. As for lowerlandowners, it has been held and it is settled law thatthey may not obstruct the flow of surface waters thatnaturally drain across or onto theirproperty from adjoining lands, O’Hara v. Los


G 012.421June, 1969

Angeles County Flood Control District, 19 Cal. 2d61, 63, 119 Pac. 2d 23 (1941); that they are liablefor damages for injury to upper land caused byobstructions which they place in the way of naturalflow, thus causing surface waters to back up orremain on land of the upper owner, LeBrun v.Richards, 210 Cal. 308, 313, 291 Pac. 825 (1930J;and that they have no right to deflect the flow ofsurface waters from their land onto adjacent land towhich such waters would not naturally flow,Cushing v. Pires, 124 Cal. 663, 665, 57 Pac. 572(1899).

4. Exceptions to Above Rules. As in the caseof all general rules, there are some exceptions to theapplicability of the above. Following are some ofthe exceptions:

a. Prescriptive Rights. The right to turnwaters from one’s land onto lands of another bymeans of artificial ditches or otherwise may beacquired by prescription; if such is continued for anumber of years required to establish adversepossession. Hails v. Martz, 28 Cal. 2d 775.

b. Tillage of Land. An exception is madewhere the interference with natural flow resultsfrom the tillage of land in the natural way. An upperlandowner is not liable for a gradual increase in thedrainage of surface waters from his land caused bythe cultivation of soil in the usual method. Coombsv. Reynolds, 43 Cal. App. 656; Bd. of Trustees ofStanford University v. Rodley, 38 Cal. App. 563.

c. City Lots. The above general rules havebeen declared inapplicable in the case of city lots,where changes and alterations in the surface areessential to the enjoyment of such lots. Los AngelesCemetery Assn. v. Los Angeles, 103 Cal. 461. Thus,an owner of a lower-lot may so improve hisproperty as to dam up the outlet and cause surfacewater, which does not assume the form of a runningstream, and which falls in the immediate vicinity tostand upon adjoining property, without incurringany liability; but he cannot, without being liabletherefor, divert such water, by means of a ditch orotherwise, onto neighboring land or an adjoiningstreet, thereby causing injury. Cloverdale v. Smith,128 Cal. 230. With respect to an owner of an uppercity lot, he must dispose of surface water insuch manner that it not his neighbor,and if he wishes to remove it

from his premises he must conduct it directly to asewer or a drain. He may not turn an adjoining lot.Armstrong v. Luco, 102 Cal. 272. The owner of abuilding is not responsible under all circumstances forkeeping rain water that has fallen onto his buildingfrom flowing to adjacent lots, but he must usereasonable care to prevent damage. Dauberman v.Grant, 198 Cal. 586.

In April, 1966, the California Supreme Courtmodified the existing law with respect to surfacewaters in California. The rights and liabilities ofadjoining land owners with respect to the flow ofsurface waters have generally been determined by therule of civil law, which the court stated to be asfollows: . . . “the owner of an upper, or dominant,estate is entitled to discharge surface water from hisland as the water naturally flows. As a corollary tothis, the upper owner is liable for any damages hecauses to adjacent property by the discharge of waterin an unnatural manner. In essence, each propertyowner’s duty is to leave the natural flow of surfacewater undisturbed.” The court further stated: “But norule can be applied by a court of justice with utterdisregard for the peculiar facts and circumstances ofthe parties and properties involved. No party, whetheran upper or a lower land owner, may act arbitrarilyand unreasonably in his relations with otherlandowners and still be immunized from all liability. Itis therefore incumbent upon every person to takereasonable care in using his property to avoid injury toadjacent property through the flow of surface waters.Failure to exercise reasonable care may result inliability by an upper owner to a lower landowner. It isequally the duty of any person threatened with injuryto his property by the flow of surface waters to takereasonable precautions to avoid or reduce any actualor potential injury.” Thus, liability for injuries causedby surface waters is to be determined by reference totort concepts rather than property law. On the issue ofreasonableness the court said: “The issue ofreasonableness becomes a question of fact to bedetermined in each case upon a consideration of allthe relevant circumstances, including such factors asthe amount of the harm caused, the foreseeability ofthe harm which results, the purpose or motive withwhich the possessor acted, and all other relevantmatter.” Other factors to be considered include: (l)The necessity for the drainage, (2) the care taken


G 012.422June, 1969

to avoid unnecessary injury to the land receiving theburden, (3) the utility of the benefit accruing to theland drained weighed against the gravity of theharm resulting to the land receiving the burden, (4)if, where practicable, the drainage is accomplishedby reasonable improving and aiding the normal andnatural system of drainage according to itsreasonable carrying capacity, or if, in the absence ofa practicable natural drain, a reasonable and feasibleartificial drainage system is adopted.

However, if the actions of both parties arereasonable under the new guidelines framed by thecourt the civil law rule prevails. In the words of thecourt: “If the actions of both the upper and lowerlandowners are reasonable, necessary, and generallyin accord with the foregoing, then the injury mustnecessarily be borne by the upper landowner whochanges a natural system of drainage, in accordancewith our traditional civil law rule. “

Keys v. Romley (1966), 64 Cal. 2d 39Action by upper landowners against an

adjoining lower landowner to enjoin her frommaintaining a dam along her property line whichcaused surface waters to accumulate on the upperowner’s property, and cross-action by the lowerowner to enjoin upper owners from dischargingsurface waters onto her land in a concentratedmanner in increased volume and acceleration.Judgment enjoining lower owner from maintainingher dam and from interfering with surface waterflow through a ditch on her property reversed withdirections.

This controversy involves adjoining propertyowners in the City of Santa Barbara. The plaintiffsand their predecessors in interest, owners of upperground, improved their property by the constructionof 48 apartment units and adjacent paved parkingarea. Their parking area was bounded by a 6-inchasphalt berm which channeled surface waters to thecorner of their property, and from there the surfacewaters traveled across defendant’s property througha defined swale. The amount of surface runoff wasnecessarily increased when the improvementsrendered impervious the previously existing bareground. The defendant, the lower owner, found thatsurface waters which formerly spread fanwiseacross her property now flowed in a concentratedman-

ner and in increased volume and acceleration.Therefore she constructed a dam along her propertyline, the effect of which was to back surface waters uponto plaintiffs’ property. This mutual vexationresulted in each landowner seeking injunctive reliefagainst the acts of the other.

The trial court found that plaintiffs’ improvementshad indeed concentrated waters and increased thevolume of flow onto defendant’s land. But it alsofound that plaintiffs had no alternative method ofdisposing of surface waters except across defendant’sproperty and that defendant would not be appreciablydamaged by the increased flow in a confined manneracross her property. Therefore plaintiffs werepermitted by the court to construct an open ditch 6 feetwide and one foot deep across the width ofdefendant’s property, the ditch to be maintained atplaintiff’s expense. Defendant was enjoined frommaintaining her dam and from interfering with theflow of surface waters through the ditch. Thedefendant appeals from this judgment.

The rule of law applicable to the foregoing facts isdiscussed at length in Keys v. Romley, and weconsider it controlling here. As indicated above, thecourt found plaintiffs had no alternative availableother than the means they selected to dispose ofsurface waters. It may be that implicit therein is adetermination of reasonableness. Nevertheless, wemust return the cause for a finding on thereasonableness of defendant’s conduct and forweighing the respective conduct of the parties inaccordance with the rule described in Keys v. Romley.

The judgment is reversed and the cause remandedwith directions to the trial court to redetermine theissues in conformity with the views expressed inKeys. The parties are to bear their own costs onappeal.

Pavliotti v. Acquistanace (1966)

G 012.422 Rights and Obligations of CitiesRespecting Surface Waters:

1. Police Power. As heretofore stated, the firstquestion a city must ask itself in determining whetherit has any constitutional liability for surface waterdamage is whether the injury is one which would giverise to a cause of action if inflicted by aprivate person. If a private person


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would not be liable, then neither is the city liable. If,however, a private person would be liable, we mustthen ascertain whether the city is excused fromliability because of its “police power.”

The term “police power” is broad and flexible,and has never been properly defined by the courts.In general, it consists of the power of a governmentto enact laws and do things, within constitutionallimits, to promote order, safety, health, morals, andgeneral welfare of society. Because of such power, acity is not subject to the same restrictions as aprivate person with respect to the control of surfacewaters. To the extent that, in making a publicimprovement, a city is lawfully and properlyexercising its police power, it is not liable forproperty damage caused by changes in the naturalflow of surface waters, if such changes in naturalflow are incidental to the making of the publicimprovement. Lampe v. City and County of SanFrancisco, 124 Cal. 546. This assumes. however,that:

a. The taking or damaging of private propertyis so essential to the public health, safety, andmorals as to be justified under the police power;

b. The city is using reasonable care anddiligence in proceeding with the publicimprovement. House v. L.A. Flood Control Dist.,25 Cal. 2d 384.

c. The city is not needlessly inflicting injuryupon private property. House v. L.A. Flood ControlDist. 25 Cal. 2d 384.

d. The city’s actions do not constitute atrespass upon private property. Womar v. City ofLong Beach, 45 Cal. App. 2d 478.

2. Specific Situations. Let us now consider howthe courts have applied the above-mentioned rulesin the following specific situations:

a. Public Streets Constructed at Grade Higherthan Adjoining Lands, Causing Surface Water toAccumulate and Stand on Adjoining Lands. Let usassume that a public street is constructed at a gradehigher than that of abutting upper lands, thuscausing surface waters, which formerly flowed fromthe upper lands onto and over the street area, toaccumulate and stand on the upper lands. Is cityliable for damage caused thereby? Generally, no.

As early as 1899, in the case of Lampe v. City andCounty of San Francisco, 124 Cal. 546, 57 Pac. 461,the California Supreme Court held that a city is notliable for such damage, where such waters had notbeen flowing in a natural channel, even though thegrade of the street had been raised about five feetabove the level of the plaintiff’s adjoining lot, and hadcaused an accumulation of surface waters within suchlot, together with flooding of a dwelling housebasement. The decision was based on the theory that acity is not liable for incidental damage resulting fromthe proper and lawful exercise of its police power. Thecourt expressly agreed with ‘the doctrine that amunicipality is not bound to protect from surfacewaters those who may be so unfortunate as to ownproperty below the level of the street.”

This assumes, however, that such waters were notcaused to be diverted onto other lands, where theyformerly did not go, that the damage was not causedbecause of an unnecessarily high street grade, and thatthe damage was not caused by negligence in planningand constructing the street. If the damage wasneedlessly inflicted by an unnecessarily high grade, orby negligence, the city is liable. House v. Los AngelesFlood Control District, 153 Pac. 2d 950.

b. Public Streets Constructed at Grade Higherthan Adjoining Lands, Causing Obstruction to Flow ofSurface Water which has Formed Itself a DefiniteChannel, said Channel Not Being a Watercourse. Letus assume that the surface water which has beenobstructed by the street, which is constructed at gradehigher than the adjoining lands, did not formerly flowin an ordinary diffused state but, owing to theconformation of the adjacent country, had formeditself a definite channel in which it was accustomed toflow. Let us assume that this channel did notconstitute a natural watercourse or stream as such isdefined by law. Let us further assume that this channelwas either entirely blocked by the street, or partiallyblocked in that a culvert constructed to handle thiswater was too small or otherwise inadequate. Let usassume that as a result, water was caused to turn back,accumulate, and stand on the lands through whichsuch water formerly flowed. Is the city liable fordamages? Yes.

This is an exception to the rule hereinabove stated inthe immediately preceding paragraph


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(a). The courts here found that a channel such as theone above described, even though it is not awatercourse, possesses so many of the attributes ofa watercourse that the rule applicable towatercourses (hereinafter set forth in Part II of thispaper) should prevail. Los Angeles Cemetery Asm.v. Los Angeles, 103 Cal. 461.

c. Same Situation as Above, Except thatCulvert Constructed to Handle Water Is Too Smallto handle Unexpected Flood which Could Not NaveReasonably Been Foreseen. Where a city, in theconstruction or maintenance of a culvert or stormsewer, has sufficiently provided for the ordinaryflow of surface water, and has not been guilty ofnegligence in the construction or maintenance of theculvert or storm sewer, it is not liable for damagesresulting from the failure of the culvert or sewer tohandle an extraordinary flow of water, by reason ofan unexpected flood, which could not havereasonably been foreseen. Los Angeles CemeteryAsnn. v. Los Angeles, 103 Cal. 461. It is a questionof fact to be decided by a jury whether the floodwas extraordinary or could have been reasonablyforeseen. If it could have been reasonably foreseen,the city is responsible.

d. Public Street Constructed at Grade Higherthan Adjoining Lands, Causing Diversion of Wateronto Lands Where Such Waters Did Not FormerlyFlow. Let us assume that the construction of apublic street, at a grade higher than that of adjoininglands, not only causes water to accumulate andstand on the upper lands through which theyformerly flowed, but also causes such waters toflow onto lands where they never formerly flowed.Is the city liable for damage to the last mentionedlands? Yes.

Here we have a situation where the street didn’tmerely prevent water from flowing off the upperlands, but actually turned such waters from saidupper lands onto new lands which formerly didn’treceive them. The flow of water was not merelyobstructed. It was also diverted. The city has thuscommitted a trespass upon the lands which formerlydidn’t receive the waters. The city is liable fordamages even if the high grade were necessary, andeven if there were no negligence. “Trespass” createsthe liability. “Police power” is no defense. Womarv. City of Long Beach, 45 Cal. App. 2d 478.

e. Public Street So Constructed that WaterAccumulates Therein, and Then Is Discharged onCertain Adjoining Lands in Manner or QuantityDifferent than Before. Let us assume that a publicstreet is so constructed that water accumulates therein,either because water falling on the street can’tpercolate through the pavement, or because the streetis constructed at a grade lower than adjoining lands,causing water to flow from said lands onto the street.Let us also assume that the water so accumulated inthe street is then caused to flow onto certain adjoiningprivate lands in quantity greater than or in mannerdifferent from that which would result underconditions of natural flow. Is city liable for flooddamage caused thereby? Yes.

Where surface waters are collected on a City streetand sent or caused to flow onto abutting private landsin quantity greater than or in a manner different thanunder natural flow conditions, the courts havegenerally held the public agency liable for resultingflood damage. Such decisions appear to be based onthe theory that a public agency, having collected waterat a particular point, has a duty to provide an adequatemethod for carrying it away, and that if it fails toperform this duty it is guilty of negligence or trespassin making the public improvements, and has thustranscended the scope of its police power. Having thusdamaged private property for a public purpose, in amanner not justified under the police power, the citymust make compensation under Article I, Section 14of the California Constitution, just as it would berequired to do in exercising the power of eminentdomain. House v. Los Angeles County Flood ControlDistrict, 25 Cal. 2d 384, 153 Pac. 2d 950 (1944).Womar v. Long Beach, 45 Cal. App. 2d 643,114 Pac.2d 704 (1941). In Los Angeles Brick and ClayProducts Co. v. Los Angeles, 60 Cal. App. 2d 478, 141Pac. 2d 46 (1943), the court held that a municipality isnot exempt from liability for trespass caused by itscorporate act, but is liable for damages caused by thedumping of storm water onto privately owned land,even though each act in constructing a streetimprovement is done according to statute. The courtfurther held that it was not necessary for plaintiff toallege or prove that defendant was negligent increating a nuisance, since a trespass voluntarilycommitted causes no less detriment than one resultingfrom neglect. The court ob-


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served that “defendants achieved exactly what theyset out to do, namely, to send ponded flood watersfrom public streets onto plaintiff’s private acres.” InStanford v. San Francisco, 111 Cal. 198, 43 Pac.605, the city was held liable for damage to privateproperty resulting from the paving of a street where,because of such paving, water which previouslysank into the soil was made to accumulate above thegrade of the street and be discharged onto plaintiff’sland.

f. Public Drainage System with InadequateOutlet. Let us assume that a city has a publicdrainage system, consisting of gutters, ditches,and/or storm sewer lines, designed to collect anddispose of surface waters which are collected in citystreets or other public properties. Let us furtherassume that said drainage system conducts anddischarges such waters, not into a natural stream,but onto a natural swale or draw in private property,in quantities greater or in manner different thanunder conditions of natural flow. Is the city liablefor resulting flood damage to the private property?Yes.

A very recent case on this matter is Steiger v.City of San Diego, 163 A.CA. 131 (August, 1958).Defendant subdividers presented subdivision plansto defendant City of San Diego, providing for asystem of drainage, storm drains, and Highways.The plans were approved by the City, and theimprovements were constructed, approved, andaccepted by the City, and became a part of the city’ssystem of public works. The system of drains wasso constructed that rain water collected therein wasconducted through a culvert under a public streetand into a draw or swale on plaintiff’s property. Theinstalled drainage system included lands which werenot a part of the natural basin. The drainage systemcaused considerable increase in the flow of watersinto the draw within plaintiff’s land, causingconsiderable erosion and damage. The Court heldthat the swale or draw in plaintiff’s land did notconstitute a natural watercourse, that the city wasliable for damages, under the provisions of ArticleIS Section 14, of the Constitution, even though therewas only damage to property and no taking ofproperty; and that the city was not entitled to aneasement in return for payment of such damages.

In Callens v. County of Orange, 129 Cal. App.2d 255, 276 Pac. 2d 886 (1954), the County was

required to pay compensation where, through theconstruction and deepening of ditches, it had divertedand accumulated surface waters from areas that wouldnot normally drain across plaintiff’s land, and hadfailed to provide an outlet therefor. It was found thatthe work was done negligently, and that saidinterference with natural conditions resulted inplaintiff’s land being inundated by a violent dischargeof water with resultant damage which under naturalconditions would not have occurred. The county wasfound to have exceeded its police power.

In Bacigalupi v. Bagshaw, 87 Cal. App. 2d 51, 196Pac. 2d 66, it was held that a county could notlawfully, to protect two county highways, divert stormwaters to a certain location and there leave suchwaters to spread out over the adjoining privateproperty; that it was its duty, having collected suchwaters at that point, to provide an adequate method ofcarrying them away.

g. Construction of Levees Along a Stream, inSuch Manner as to Obstruct Flow of Surface Watersinto Stream. Let us assume that a city, in order toprotect itself from flood damage resulting fromoccasional overflows of a river or other naturalstream, constructs a system of levees along the banksof the stream. let us also assume that although thelevees protect private property from damage whichmight otherwise be caused by “flood waters”overflowing the banks of the river, they also have theeffect of obstructing the natural flow of surface watersfrom private property into the river or stream, therebycausing surface water to accumulate and stand on theprivate property. Is the city liable for resulting damageto the private property? Generally, no.

In O’Hara v. Los Angeles County Flood ControlDistrict, 18 Cal. 2d 61,119 Pac. 2d 23 (1941), thecourt held that the same rule should apply in thissituation as is applied where a city raises the grade ofa public street, thereby obstructing the natural flow ofsurface waters from adjoining lands onto and acrossthe street; that is. that such damage is an incidentalconsequence of the lawful exercise of the policepower (flood control) and therefore non-compensible.

This assumes, of course, that the damage was notunnecessarily inflicted, ant that the damage


G 012.422dJune, 1969

did not result from negligent construction of thelevees. For example, if the obstruction of waterscould have reasonably been minimized by theconstruction of flood gates or openings in thelevees, the City might be held liable on the groundthat it negligently constructed the levees, and causedunnecessary damage. This would be a question offact to be determined by the court.

h. Public Improvements Constructed bySubdividers, in Accordance with Plans andSpecifications Approved by City, and Accepted byCity and Made a Part of its Public Works System.The Subdivision Map Act provides that control ofthe design and improvement of subdivisions isvested in the governing bodies of cities andcounties, and that every city and county shall adoptordinances regulating and controlling the design andimprovement of subdivisions. Government CodeSection 11525. “Design” is defined as referring to“Street alignment, grades, and widths, alignmentand widths of easements and rights of way fordrainage and sanitary sewers and minimum lot areaand width.” Government Code Section 11510.“Improvement” is defined as referring to “only suchstreet work and utilities to be installed, or agreed tobe installed, by the subdivider on the land to be usedfor public or private streets, highways, ways, andeasements, as are necessary for the general use ofthe lot owners in the subdivision and localneighborhood traffic and drainage needs as acondition precedent to the approval and acceptanceof the final map thereof.” Government Code Section11511. The Act further provides that the governingbody of any city or county may disapprove atentative map or maps of a subdivision because offlood hazard and inundation, and require protectiveimprovements to be constructed as a conditionprecedent to approval of the map or maps.

In accordance with said Act, cities usuallyrequire subdividers to construct streets, sanitarysewers, storm drains, and other improvements inaccordance with plans and specifications preparedor approved by the city. Upon completion of suchimprovements, a city usually accepts them, and theybecome a part of the city’s public works system. Is acity excused from responsibility or liability forsurface water damage caused by said improvements,merely because they were con-

structed subdivider rather than by the city? No!

The law is well settled that in the above situationthe city, and not the subdivider or contractor, isresponsible for said damages. Steeger v. City of SanDiego, 163 CA 2d 110. A different result might beobtained, however, if the damage resulted from thefailure of the subdivider or contractor to comply withthe plans and specifications approved by the city andthe city did not, because of such non-compliance,accept the improvements.

In a recent case a subdivison and an improvementto some church property were built above theplaintiff’s property. The development of thesubdivision increased the amount of water runoff ontothe church property but there was no evidence ofdiversion. The water broke into three channels on thechurch property, one of which flowed acrossplaintiff’s property. The construction of theimprovement on the church property diverted waterinto the channel flowing across plaintiff’s land. TheCity had an existing easement over plaintiff’s propertyfor drainage of that amount of water which could behandled by a 20” culvert adjacent to the propertywhich drained into a natural channel on the property.Due to the increased flow caused by the diversion theCity widened the channel on plaintiff’s property andreplaced the 20” culvert with a 24” culvert. This wasdone to alleviate the spilling over onto plaintiff’sproperty of water which could not be handled by the20” culvert. The following were held to be acts ofinverse condemnation. l: The diversion of drainagewaters. The approval of subdivision maps and planswhich include drainage systems constitutes asubstantial participation incident to the serving of apublic service. 2: The construction of the 24” culvert.The discharge of the additional waters caused by thediversion increased the burden on plaintiff’s property.Liability for both of the above was predicated on thetheory that the City failed to appreciate and providefor the probability that that the drainage system andthe larger culvert, functioning as deliberatelyconceived, would result in some damage to privateproperty. 3: The enlargement of the channel onplaintiff’s property The City enlargedthe ditch to accommodate the


G 012.422eJune, 1969

increased flow without the owner’s consent andcommitted a trespass in so doing.

Frustuck v. City of Fairfax (1963),212 Cal. App. 2d 345

i. Streets, Drains, and Other SuchImprovements Constructed by Subdivider inAccordance with Plans and SpecificationsApproved by a City, but Not Accepted by City.Who has the responsibility for water damage causedby streets, sewers, drains, and other improvementswhich a city requires a subdivider to construct,which are constructed in accordance with plans andspecifications approved by a city, but which a cityrefuses to accept as part of its public works system?In the recent case of Youngblood v. City of LosAngeles, 158 A.C.A. 151 (1958), an action fordamages to property resulting from increased flowof waterin a natural stream allegedly caused bypaving and other subdivision improvements, anonsuit in favor of the city was sustained on theground that, although the city had approved thesubdivision map and the construction of subdivisionimprovements, it had not accepted suchimprovements until after the damage had occurredand, therefore; no liability on the part of the cityarose by reason of the manner in which thesubdivider was doing the work, under the ruleannounced in Hoover v. County of Kern, 118 Cal.App. 2d 139, 257 Pac. 2d 492 and Wallner v. Barry,207 Cal. 465, 279 Pac. 148. The Hoover casemerely involved a defect in a street resulting fromnon maintenance. The Wallner case, however,involved flooding caused by construction of a “fill”and culvert, as part of a subdivision, which were sonegligently designed and constructed as to cause theimpounding of water. The subdivision map and theplans for said improvements had been approved bythe city, and dedication of the streets had beenaccepted by the city prior to their completion. Thecourt held that the city’s acceptance of dedicationwas conditional upon the completion andsubsequent acceptance of the improvements, andthat since the city had not yet accepted the work, thecity was not liable for damage resulting from theirnegligent construction or maintenance.

Notwithstanding the above cases, we feel that thisquestion has not yet been completely resolved. If,by virtue of its powers of control over designand improvements and over drainage, a cityshould require a subdivider to construct

streets, drainage, and other improvements strictly inaccordance to designs and plans specified by the city,and if unlawful flooding should result because of thedesign and plans required by city and not because ofany negligence in construction or maintenance, cancity evade liability merely because it failed to acceptdedication of such improvements? This would not be asituation involving negligence in construction ormaintenance, but negligent or deliberately bad design.Can it not be said that since the city has requiredconstruction of such improvements, pursuant to theSubdivision Map Act, for the benefit and protection ofpublic health, safety, and welfare, any resultantdamage to private property is damage caused for apublic purpose for which the city must paycompensation under Article I, Section 14 of theConstitution, even though the city does not accept titleto such improvements? We believe the city, in such acase, would be held liable, although we know of nocase where the issue has been squarely presented anddecided.

j. Subdivision Improvements, Other Than ThoseRequired by City, and Other Than Those Required byCity to Be Constructed in Accordance with Plans andSpecifications Approved by City. Let us assume a cityapproved a subdivision map for land which undernatural conditions is subject to frequent or occasionalfloods, without requiring the construction of anydrainage facilities to prevent such flooding in thefuture, and future flood damage results. Let us alsoassume the city approves a subdivision map foranother subdivision in which the subdivider proposesto raise, lower, or otherwise change the grade of all orsome of the private lots, so that the natural flow ofsurface waters is altered, causing future flood damage.Let us assume the damage is not caused by any streets,drains, or other such improvements required by thecity. Is the city responsible and liable for suchdamage?

Section 11551.5 of the Subdivision Map Act saysthat the governing body of a city may disapprove atentative map of a subdivision because of flood hazardand inundation, and require protective improvements.It does not require the city to disapprove a tentativemap of a subdivision because of flood hazard, anddoes not require the city to insist uponprotective improvements. A person cannotcompel the Performance of, or recover in-


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demnity for damage resulting merely from the non-exercise of, powers conferred on a city by charter orstatute. There must be a plain, certain, and non-discriminatory duty to be performed for anindividual’s own benefit before a right of actionarises in his favor. The duty of the city to exerciseits powers is a political duty owing to the statealone, or to all citizens of the community. Theexercise of such powers is discretionary with thelegislative and administrative authorities of the city.35 Cal. Jur. 2d 318.

In our opinion, a city is not liable for flooddamages where the land originally was subject tosuch flooding and the city merely failed to requiredrainage improvements as a condition to approvinga subdivision map. Thus, in an action against a cityto recover damages caused by surface waters whichflowed on plaintiff’s property at an intersection ofstreets, and to abate a nuisance, the city was heldnot liable where it was shown that there existed anatural depression at or near said intersection, whichcaused surface waters to accumulate there, and thatsuch waters always collected there under naturalconditions. The fact that the city had graded andpaved the streets was held immaterial, since suchgrading or paving was not the real cause of theinundation. The court further held that where a cityis confronted with a difficult drainage problem in alow-lying area, in its effort to combat flood watersand to solve the problem, the city could not be heldstrictly accountable to the owner of property whichwas still flooded after grading and paving of streetsmerely because the city failed to completely remedythe existing situation. Womar v. City of Long Beach,114 Pac. 2d 704, 45 Cal. App. 2d 643 (1941).

However, the following case must be considered.

In this case, an appeal is made by defendantCounty of Los Angeles (County) and defendantGibco Construction, Inc. (Gibco) from a judgmentof the Superior Court of Los Angeles County infavor of plaintiff David Sheffet and againstdefendants. The action was brought by plaintiff, asan owner of real property, against defendants fordamages caused by surface waters and mud drainingacross and onto plaintiff’s property and into thedrainage ditch on plaintiff’s property from the landand streets owned by the defendants; for aninjunction ordering defendants to refrain from

draining surface waters across plaintiff’s land; and foran injunction ordering defendants to take correctivesteps to prevent the draining of surface waters ontoplaintiff’s land and in plaintiff’s drainage ditch inexcess of the existing prescriptive rights ofdefendants. After a court trial, plaintiff was awarded$50 in damages against both defendants, and the courtissued the following injunction:

“Defendants Gibco Construction, Inc., acorporation, and County of Los Angeles, and eachof them, are enjoined from in any mannerdischarging onto the real property of plaintiff orwithin the ditch located upon plaintiff’s property,in excess of defendants’ existing prescriptiverights, the surface waters which collect from timeto time on said defendants’ lands, walks, curbs,drives, gutters and streets, and further, saiddefendants, and each of them, are hereby ordered,directed and required, to take corrective stepswithin 240 days hereto to prevent the saiddraining of surface waters onto plaintiff’s landand upon and in plaintiff’s ditch in excess ofdefendants’ existing prescriptive rights.”

Plaintiff has owned and resided on the realproperty known as 396 East Mendocino Street inAltadena, California since 1952. Prior to March 1965,the property located across the street from plaintiffwas higher and unimproved land. In March of 1965,defendant Gibco commenced construction of asubdivision on the property, then known as Tract No.29892. The property was cleared of trees and brush inMarch 1965, and grading was commenced during themonths of April and May 1965. Plans for thesubdivision were prepared by engineers employed bydefendant Gibco, and were approved by defendantCounty. Contained in the plans were two one-block-long streets: Deodara (running east and west) andOliveras (running north and south). After they hadbeen completed and had passed final inspection, theywere dedicated as public highways and accepted bydefendant County “for all public purposes and liabilityattaching thereto.” Due to this construction, thenatural area available for absorption of surface waterson the tract was reduced by 51.4 percent. Thisreduction, combined with the design ofOliveras and Deodara Streets, created anincreased and different pattern of surface-flow from


G 012.422gJune, 1973

the tract, concentrating the runoff to and downOliveras which dead-ended at its intersection withMendocino immediately north of plaintiff’s easterlydriveway apron. Prior to November 1965, plaintiffhad experienced no flow of surface water onto hisproperty from across the street. In variousrainstorms between 1965 and December 1966,water and mud from the tract flowed onto andflooded plaintiff’s property, via the overflow fromOliveras, across Mendocino and down the drivewayon the east side of plaintiff’s property, as well asmud and water from the tract being deposited in thedrainage ditch on the west side of his land. Plaintiffmade several complaints to the County and Gibco,but neither defendant took any steps to alleviate theproblem of water and mud flowing from the tract.

On this appeal from the judgment, defendantsraise five contentions: (1) the plaintiff did not actreasonably in protecting his property; (2) theinjunction is vague, confusing, and incapable ofbeing carried out; (3) in injunction does not liewhere plaintiff has only suffered nominal damages;(4) plaintiff’s drainage ditch is a natural watercourseand defendants may properly discharge surfacewaters into it; (5) by statute, defendant County isimmune from liability in this case.

California courts follow a modified rule of civillaw in determining the rights and liabilities ofadjoining, landowners with respect to the flow ofsurface waters.

Keys laid down three express rules: (1) if theupper owner is reasonable and the lower owner isunreasonable, the upper owner wins; (2) if the upperowner is unreasonable, the lower owner isreasonable, the lower owner wins; (3) if both theupper and lower owners are reasonable, the lowerowner wins.

Here, defendants argue that plaintiff failed totake any reasonable precautions to protect hisproperty from the flow of water and mud. The trialcourt expressly rejected this contention. Assumingthat the rule of Keys is applicable here, unless thereis no substantial evidence to support this finding, weare bound by the decision of the trial court.

The person who may minimize damage and fails todo so cannot recover for the excess damage occurring.On the other hand, a person who reasonably acts tominimize the damage should recover the costs of such“minimization” as damages. Where, however, theinjured person acts reasonably, by action to minimizethe damage, or by inaction which does notunreasonably increase his damages, if there is adiminution in the value of his land also involved, wesee no reason why he may not recover for the damage.

Upon an examination of the record, we havedetermined that there is substantial evidence tosupport a finding that plaintiff acted reasonably inrelation to his property. So far as the County isconcerned, however, we conclude that the increaseduse of plaintiff’s ditch, as a result of the improvement,is in the nature of inverse condemnation (the remedywhich a property owner is permitted to prosecute toobtain the just compensation which the Constitutionassures him when his property, without prior paymenttherefore, has been taken or damaged for public use.);that the County is not as a matter of law, prohibitedfrom increasing a servitude if such increase is withoutunreasonable damage to the owner of the servientestate and compensation for any diminution in theproperty’s value is paid by the County.

Since it was the trial court’s finding that the Countyacted unreasonably in accepting the dedication ofDeodara and Oliveras Streets, the layout of whichcaused the defective drainage of Mendocino Street, weare not required to resolve the question. Property isonly deemed taken or damaged for a public use if theinjury is a necessary consequence of the publicproject. (Albers v. County of Los Angeles, supra, pp.263-64.) Van Alstyne (Inverse Condemnation, supra,at page 781) states:

“It now appears settled that if the constructionor maintenance of a public project is designed toserve the interests of the community as a whole,any property damage caused by the project or by itsoperations as deliberately conceived is for a publicuse and is constitutionally compensable. On theother hand, damage resulting fromnegligence in the routine operationhaving no relation to the func-


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tion of the project as conceived, is not within thepurview of section 14, Article I, CaliforniaConstitution.”

Here, the increased burden upon plaintiff’sditch was a necessary consequence of the design ofthe tract and the creation and improvement of thestreets. However, the overflow of the streets’ crown,while resultant, was not a necessary consequence ofthe improvement to the higher ground. It is true thatdefendant County merely approved the plans andaccepted the streets, leaving the actual planning andconstruction to a private contractor, but the Countyis not thereby shielded from liability. In the instantcase, the defendant County is liable to the plaintifffor the same reasons as expressed in Frustuck, uponits approval of the plans.

Gibco’s liability, however, is a differentquestion. In the absence of something in the natureof a protective covenant, where a public entityapproves the plans for a subdivision, including adrainage system, and there is damage to adjacentproperty as a result of those improvements, thepublic entity, not the subdivider, is liable in aninverse condemnation suit.

The whole of the injunction goes to the mannerof discharging waters, none of which are within thecontrol of defendant Gibco. There has been a waiverof appeal by Gibco from that portion of thejudgment relative to the damage award of $50.There is no evidence of negligent conduct by Gibcocontributing to or causing the water or mud flowother than would naturally result from the terrainalteration and the concentration of the surfacewaters into the streets. What the facts hereestablished is that the surface waters’ runoff wasincreased in volume, and was directed andconcentrated into the public street in the expectedfashion occasioned by the approved subdivisionplan. Thus, the diversion in question, so far asGibco was concerned, was only the drainage ofsurface waters by an abutting property owners into apublic street. However, the drainage of surfacewater over a public street is a use thereof byabutting property owners which could not beunlawfully obstructed. For that reason, inversecondemnation is an accomplished fact as to anydiminution in value of plaintiff’s property caused bythe additional burden placed on the ditch, and an

injuction will not lie where the damage to plaintiff isnot unreasonable under the propriety of theimprovement. Except for the minor clean-up recoveryfor the mud occasioned during tract development andthe over-crown runoff via the plaintiff’s driveway,plaintiff’s action must be limited to damages for theloss in value of his property. But he cannot nowrequire the County to undo that which has beenaccomplished and which does not create anunreasonable increase in the burden which the landalready bore. While it is true that the surface waterdiversion may not be a part of the publicimprovement, nevertheless the resultant runoff anddiversion, were intended, is caused by theimprovement. While the public use of theimprovement obtains, the damages which also resultand which are attached thereto are within the authorityof the agency causing the improvement, to the sameextent as is the improvement itself.

In cases such as the one before us, neither theconsequentially injured party nor the courts maysuperimpose corrective authority upon public worksalready created unless they are negligentlyconstructed, or constructed in a manner unnecessary tothe public improvement. As we have pointed out, theuse of the ditch, by the increase of its burden, did notcause a different injury, though it may well haveconstituted a diminution in property value for whichplaintiff may recover. This portion of theimprovement was designed to accomplish the veryresult of which plaintiff complains. The over-dashcrown runoff, however, is but the result of negligentdesign of the crown height or road pitch, and has norelationship to the reasonableness of the publicimprovement sought to be created. As to suchunnecessary, unintentional, and negligently createdconsequences of the public improvement, we seeneither logic no reason which prohibits the issuance ofan injunction to prohibit the maintenance thereof.

In the instant case, the injunction is proper as itrelates to the over-crown runoff, and a mandatoryinjunction could issue ordering the County to ceaseengaging in such acts of negligence in themaintenance of the inadequate drainage system.

Inverse condemnation does not involve ordinary


G 012.422iJune, 1973

negligence, but rather damages which are a naturalconsequence of the public improvement. Theinjunction as issued, however, exceeds the boundsof judicial authority in the instant case as it relatesto the increased use of the ditch. Were it to beapproved in that respect, it would authorize aninjunction which would effectively negate thepower of the government to take property throughinverse condemnation.

While plaintiff did not specifically allege thathis property had been taken or damaged for a publicpurpose and therefore inversely condemned, his firstamended complaint did allege facts which wouldsupport a cause of action for inverse condemnation.The pleading alleges that defendant County allowedthe construction of a subdivision on the land abovehis property; that defendant County allowed theconstruction of and accepted the streets on saidland; that said construction reduced the naturaldrainage area on said land, causing substantialamounts of surface water to be discharged onto hisproperty and overload his drainage ditch; and thatthese surface waters continue to be discharged ontohis land. These facts, if true, constitute a taking byway of damage to plaintiff’s land and for a publicpurpose. Adequate and timely notice and demandare alleged. Thus, a cause of action in inversecondemnation is substantially set forth, thoughsubject to improvement by amended pleading.

Defendants contend on appeal that plaintiff’sdrainage ditch is a natural watercourse. However,neither defendant raised this theory until defendantCounty argued it in its Points and Authorities datedNovember 1, 1967. Neither defendant set forth inany pleading any allegation that the ditch was anatural watercourse. Neither defendant requested ormoved to conform any pleading to any evidenceconcerning the issue of a natural watercourse. OnMarch 3, 1967, plaintiff, in his proposed findings offact, included a finding that the drainage ditch wasnot and had never been a natural watercourse. Thedefendants objected to this proposed finding on theground it was unnecessary, and the courts deleted it,indicating that the proposed finding concerningdefendant’s prescriptive rights covered the point.Defendants did not request a special finding on theissue of a natural watercourse. The defendants maynot now complain on appeal of defects in the

court’s findings for which they are responsible.

However, on the evidence in the case before us,we would conclude that defendant’s arguments wouldfail on the merits. Pursuant to exception (2) set forthin Albers, the County correctly argues that an upperlandowner may discharge surface waters into a naturalwatercourse and increase its volume withoutsubjecting itself to liability for any damage sufferedby a lower landowner, even if the stream channel isinadequate to accommodate the increased flow.(Archer v. City of Los Angeles, supra, 19 Cal. 2d 19).It is the County’s contention that because of its longand continued use, plaintiff’s drainage ditchconstitutes a natural watercourse.

We have heretofore discussed the right of theCounty to increase the burden upon the ditch,provided recompense for diminution of value, if any,is paid under the theory of inverse condemnation.Plaintiff’s complaint, however, goes beyond theproblem of excess water in his ditch. His complaint isthat the water races down the new street, acrossMendocino, and down his driveway, flooding acrosshis yard, depositing debris, as well as causing erosion.We are therefore not confronted with the narrowproblem of increased waters through the ditch, as theCounty would suggest. In the instant case, the Countysuggests that a grate and drain could have beenconstructed by plaintiff at his driveway apron tofunnel the waters across his land to the drainage ditch.While this may be a possible solution, it goes more tothe damage occasioned by the introduction of thewaters onto plaintiff’s property than to the issue ofreasonable or unreasonable action by plaintiff.(Frustuck v. City of Fairfax, supra, pp. 368-69.)Certainly, whatever plaintiff must erect on hisproperty he is entitled to both the cost of such erectionand the damage caused by the burden requiring suchprotective structures.

The suggestion of the County above discussedmight have been a solution to the problem;nevertheless, the obligation to prevent future damagefrom the County’s maintenance of its negligentlyconstructed street was that of the County. The burdenis on the County to construct its streets in such amanner as to accomplish the purpose forwhich they were intended. This includes provid-


G 012.43June, 1973

ing the road with such crown or pitch as to divertthe oncoming surface waters in the directionintended. If the approved design fails to meet thepurpose for which it was created and the conditionof the street results in causing damage, itsmaintenance in such condition may be enjoined, forthe resultant damage is not “for the public use.”

The issuance of the injunction, so far as itrelates to the use of the ditch, while erroneous andrequiring reversal, was a clear attempt by the trialcourt to provide relief to plaintiff for the damage hehas been occasioned. Though that remedy cannot beaffirmed, the determination of liability need not bedisturbed so far as defendant County is concerned.So far as the injunction related to over-crownrunoff, the injunctive relief is affirmed.

As to defendant County, the judgment isreversed as to the relief sought to be granted as toany increased use of the ditch for water diversionpurposes only, and the case is remanded to the trial -court on the issue of damages only, in conformitywith this opinion.

As to defendant Gibco, the judgment isreversed as to both liability and damages.

Sheffet v. County of Los Angeles 3 Ca 3d 720(1970) .

With respect to flood damage caused bychanging the grade of all or part of some of theprivate lots, it is our opinion that the city is notresponsible if it didn’t require such change of gradeas a condition of approval of the subdivision map,and if the city itself didn’t change such grades.However, we expect litigation on this point; it willprobably be contended that a city has a duty torefuse approval of a subdivision map unlessadequate drainage is provided. In our opinion, a cityhas no such duty, but we know of no Appellate casesquarely deciding the issue.

G 012.43 Floods Attributable to FloodWaters: We have hereinabove discussed liabilityfor flood damage caused by “surface waters.” Now,let us consider the responsibility of a city for flooddamage caused by “flood waters.” As heretofore

pointed out, “flood waters” are waters which wereonce part of a natural watercourse or stream but haveescaped therefrom and overflowed on adiacentterritory.

a. Obstructing Natural Flow of Waters in aNatural Watercourse, or Diverting Waters from aStream. It is well established that no person has anyright to obstruct the flow of a natural watercourse, norto divert water from its natural channel into anotherchannel, if the result is to cause an overflow of waterupon land of another that would not have reached suchland had the artificial change not been made. Clementv. State Reclamation Board, 35 Cal. 2d 628, 220 Pac.897 (1950). Nor may a person divert the flow of waterfrom its natural and accustomed channel to anotherchannel of even the same stream if the result is toprecipitate water on lands which would not otherwisehave received it. Hellman Com. Tr. & Sav. Bank v.Southern Pacific Co., 190 Cal. 626, 214 Pac. 46(1923).

The above rules apply alike to natural persons,private corporations, municipal corporations, andpolitical subdivisions of the State, whether theobstruction or diversion is made on one’s own land oron land of another with latter’s consent. Smith v. LosAngeles, 66 Cal. App. 2d 562, 153 Pac. 2d 69 (1944).In view of the above rules, therefore, it is obvious thatif a city should construct any public improvementswhich obstruct the flow of a natural watercourse, ordivert waters therefrom, with consequent overflow ofwaters on lands which would not otherwise receivethem, the city is liable for resultant damage, underArticle I, Section 14 of the Constitution.

b. Floods Attributable to Dikes, Levees,Embankments, and Other Improvements Constructedto Protect Lands from High Waters in a Stream. It iswell settled in California that flood waters are acommon enemy against which owners of land mayconstruct defensive barricades, provided they do notobstruct the flow of water in a stream nor divert watertherefrom. The principles relating to this right ofprotection were stated by the California SupremeCourt in Weinberg Co. v. Bixby, 185 Cal. 87, 196 Pac.24 (1921), as follows:


G 012.43aJune, 1969

“The doctrine of the common law relating toprotection against flood overflow of rivers, andwhich has been adopted by the California courts,recognizes such flood waters as a common enemywhich may be guarded against or warded off by onewhose property is invaded or threatened, byobstructions which are merely defensive in theirnature and not calculated to interfere with thecurrent of the water in its natural channel.

“This rule has been so often cited, approved,and commented upon by the supreme court of thisstate as applied to dikes and embankments byproperty owners to prevent overflow of their landsby the flood waters of the Sacramento River andsimilar streams of this state, even though the resultof such obstruction has been to throw an increasedvolume of the flood upon opposite or lowerproprietors, that it is not necessary to review thedecisions at length . . . (Emphasis ours).

“We recognize the limitation in all of thesecases that such right of self-protection does notpermit of any obstruction of or interference with thenatural channel of the stream or diversion of theflow of the water in such channel.

“The fact that a land owner avails himself ofthe right to repel vagrant waters of a river byembankments does not, in the absence of somefurther circumstances or set of circumstances,impose upon him any obligation to maintain suchobstruction, or to refrain from restoring naturalconditions. There is nothing in the doctrine of self-protection against flood waters to prevent a landowner from applying it to a single acre of his landsor the conservation of a single annual crop bytemporary structures.”

In Green v. Swift, 47 Cal. 536 (1874), theSupreme Court held that owners of land adjacent tothe Sacramento River that had been damaged as aresult of work done pursuant to authorization of thelegislature for the purpose of protecting the City ofSacramento could not recover damages, suchdamage being incidental to the lawful exercise ofthe police power.

In Clement v. State Reclamation Board, 35 Cal.2d 628, 220 Pac. 2d 897, it was held that the statecould take any action to protect all landowners in anarea from flood waters, which could be

taken for his own protection by an individuallandowner in preventing waters of a stream fromoverflowing his land, without payment ofcompensation.

However, although a person may install, maintain,and operate structures to protect his property againstflood waters, in order to avoid liability the acts of theowner of such structures must be reasonable under thecircumstances. Wade v. Thorson, 5 Cal. App. 2d 706,43 Pac. 2d 592 (1935). Whether his conduct isreasonable will be determined by existing conditionsand not by the subsequent consequences of his acts.Jones v. California Development Co., 173 Cal. 565,160 Pac. 823 (1916).

c. Increased and Accelerated Flow of surfaceWaters into and In a Creek, Resulting fromUrbanization, Construction of Storm Drains, and fromStraightening, Widening, and Deepening of a Portionof the Creek, Without Improving Outlet of Creek. Letus assume an area drained by a creek is transformedinto residential and business districts, and as a resultsurface waters which formerly followed no definedcourse are confined to ditches and channels emptyinginto the creek. Let us further assume that publicconcrete storm drains are later constructed to improvethe drainage. As a result of the urbanization, less wateris absorbed into the earth, and more is caused to flowinto the creek; and as a result of the drainageimprovements, the flow of such water into the creek isaccelerated. Let us further assume that the citystraightens, widens, and deepens a portion of the creekso that it can receive such increased runoff, but doesn’timprove the lower portion or outlet of the creek, withthe result that the lower portion of the creek can’thandle the increased and accelerated flood, so thatlower riparian lands are flooded. Is the public agencywhich made such improvements responsible for suchdamage? No, not if the drainage improvementsfollowed the natural drainage of the area.

The above situation was presented in the case ofArcher v. City of Los Angeles, 19 Cal. 2d 19. Thecourt held that there is no diversion of surface watersif such waters, flowing in no defined channel, are for areasonable purpose gathered together and dischargedinto a stream that is their natural meansof drainage, even though the streamchannel is inadequate to accommodate


G 012.5June, 1973

the increased flow. It further stated that while alandowner may not collect surface waters anddischarge them upon adjacent land, he maydischarge them for a reasonable purpose into astream into which they naturally drain, withoutincurring liability for damage to the lower landcaused by the increased flow of the stream.

The court further held that the straightening,widening, and deepening of the channel of thestream to improve drainage entails no diversion ofwaters therein, and therefore creates no liability forflood damage suffered by lower riparian lands.

The above assumes, however, that the drainageimprovements follow the natural drainage of thecountry. If water is diverted out of its naturalchannel and diverted into a different channel, thereis then liability for resultant flood damage.

d. Floods Attributable to Obstructions to Flowof Escaped Flood Waters. It is well settled not onlythat a person may protect his property from highstream waters by levees, etc., but also that he mayprotect his land from escaped stream waters,referred to as flood waters, by obstructing the flowthereof onto his land, even though such obstructioncauses the water to flow onto land of another.Horton v. Goodenough, 184 Cal. 451, 194 Pac. 34(1920); Williams v. California Pacific CoastAggregates, 128 Cal. App. 2d 77, 276 Pac. 2d 28(1954).

e. Improvements Constructed by Subdividers.What is a city’s liability for “flood water” damagecaused by improvements constructed by asubdivider? The rules applicable in this situation aresimilar to those applicable where the damage iscaused by “surface waters” rather than by “floodwaters.” See Section G 012.422, Subsection 2, i andj.

G 012.5 Personal Conduct: A City employeewithin the capacity of his office can incur liabilityfor the City. Therefore, the design engineer must, byability, training, good judgment, and constantattention to his work, protect the City from charges(which would have foundation) of negligence indesign. In the absence of negligence, a damage ortaking of property which occurs, and which was thenatural or probable result of the design(and hence foreseeable) subjects the City

to liability, since this damage is interpreted as havingbeen intended.

No personnel of the Bureau of Engineering shallexpress either written or oral opinions to the publicabout City liability in any actual or potential claimagainst the City. The design engineer shall not expressor imply legal responsibility on the part of the City inreports or other official instruments; nor shall he dounauthorized remedial work, since this may imply anadmission of legal responsibility on the part of theCity. All calls requesting information on such mattersshall be referred to the District or Division Engineer.

G 013 BUREAU RESPONSIBILITYThe Bureau of Engineering plans, designs, and

prepares the construction drawings, estimates, andspecifications for all streets, bridges, and otherstructures, sanitary facilities, storm drains, and relatedpublic improvements, and subsequently handlescontract documents and certain contractualrelationships during construction. It is responsible forthe engineering features of all subdivisions, landacquisitions, and related activities, together with thebasic assessment act procedures involved in publicimprovements financed by that method. The Bureau ischarged with the responsibility for all basic andproject surveying and for preparation of all basicmaps, and is the custodian of all records pertainingthereto. It is also custodian of all original maps, plans,records, and other data related to the public workswith which the Bureau is concerned. It acts ascoordinator with Federal, State, and County agenciesin the financing, design, and construction of publicworks facilities.

The Organization Chart of the Bureau ofEngineering is found in the front of this Manual. Thedesign of storm drains is the responsibility of theDrainage Systems Engineering Division and theEngineering Districts. Other duties and responsibilitiesof the Bureau are covered in other parts of theManual.

G 013.1 District Responsibility: Each DistrictOffice is responsible for the design and processing ofstreets, sewers, and storm drains of all City projectswithin the district, unless a project is specificallyassigned to another design office by the CityEngineer. It is also responsible for the designor checking of Los Angeles CountyFlood


G 012.5June, 1973

Control District projects and the design of stormdrains for State highways within the district. Eachdistrict maintains its own reference maps andrecords. A map of Engineering Districts is found inthe front of this Manual.

Although the design office loses direct controlover the project after the Division/District Engineerhas signed the tracings, that office should maintainaccurate and current knowledge of the progress ofprojects which have been designed by that office. If,at any time, the design office feels that any of theprojects are not making satisfactory progress,contact should be made with the responsibledivision (Figure G 750) to determine the cause ofthe delay and what steps, if any, can be taken toexpedite the project.

G 013.2 Drainage Systems EngineeringDivision Responsibility: The Drainage SystemsEngineering Division is responsible for the designand processing of all storm drain projects within theCentral District, and also serves as consultant to theDistrict Offices’ storm drain projects which havespecial requirements or cover extensive areas. Itestablishes procedures and initiates Standard Plansfor storm drains and appurtenances; compiles datafor drainage maps; designs stormdrains for State Freeways throughout the

City; coordinates, reviews, and processes, matterspertaining to the Los Angeles County Flood ControlDistrict Programs within the City; operates anExperimental Hydraulic Research Laboratory for theinvestigation and solution of special hydraulicproblems beyond the scope of general engineeringknowledge; and gathers rainfall data throughout theCity.

G 013.3 Personal Responsibility: The District orDivision Engineer delegates to the Project Engineer orsquad leader individual responsibility for “followthrough” on his assigned project, from the issuance ofthe work order to the approval of the plans by theDistrict or Division Engineer. This means that theProject Engineer or squad leader shall expedite thepath of plans through other persons, bureaus, anddepartments in order that scheduled dates for designcompletion can be met. In those instances when theProject Engineer or squad leader finds that a delaywill occur which is beyond his scope of authority toovercome, it shall be his duty to notify the District orDivision Engineer.

The designer is responsible to his Project Engineeror squad leader and shall discuss all design problemswith him.

G 020 PROJECT TYPES AND AGENCY JURISDICTIONS

The types of drainage projects within the Cityare dependent upon the agency of jurisdiction overthe project. Determination of the agency ofjurisdiction is based upon the type of drainagefacilities involved. These facilities are divided intothree classes:

1. Major Watercourses, such as the LosAngeles River and Compton Creek, which are underthe jurisdiction of the Corps of Engineers, U. S.Army.

2. Secondary Watercourses, such as LagunaDominguez Channel and Aliso Creek, which areunder the jurisdiction of the Los Angeles CountyFlood Control District.

3. Local Drainage Facilities, which are underthe jurisdiction of the City of Los Angeles.

G 021 CORPS OF ENGINEERSThe Corps of Engineers, U. S. Army, designs

and constructs the major flood control facilities asshown on Figure G 023. These projects are fi-

nanced by federal funds and need no authorization orapproval from any state or local agency. Since thesemajor facilities must accept contributary flows,however, the City usually reviews each design toensure that all existing tributary drains within the Cityhave a proper outlet, and to request that planned orproposed projects be accommodated. The review isusually assigned to the City engineering district officeof jurisdiction.

G 022 STATE DEPARTMENT OFTRANSPORTATION

State Projects within the City are financed andconstructed by the State. Generally, the State designsits own highways and freeways and the City designsall drainage facilities required under agreement withthe State. However, the Transportation EngineeringDivision designs all city streets constructed as part ofState Freeway projects and is responsiblefor processing all State Projects withinthe City. Drainage facilities for


G 023June, 1969

State highways, other than freeways, are designed toCity standards and may be designed by the CityDistrict Office of jurisdiction. Drainage facilities forState Freeways are designed by the Storm DrainDesign Division.

Freeway storm drains are classified as “onsite”and “off-site”. On-site drains are those constructedentirely within the State right of way. They aredesigned to the following State standards:

a. For normal design, use a 25-year stormfrequency.

b. For sumps, use a 50-year storm frequency.(This design is not covered in this manual.)

Off-site drains are those constructed outside ofthe State right of way to pick up or discharge runoff.They are designed to City standards and criteria.

Freeway culverts are designed for a 50-yearstorm. The State’s prime considerations are toprotect the freeway embankment or roadway fromflooding on a 50-year frequency storm and toprovide facilities which maintain existing drainageconditions. Particular care is taken to ensure that nodamming or diversion occurs. Accommodations forproposed (or future) drainage facilities beyond thescope of the freeway project must be financedthrough a betterment agreement with the City.

Storm drains in State highways other thanfreeways are maintained by the City Bureau ofSanitation, except those drains constructed by theLos Angeles County Flood Control District. On-sitefreeway drains are maintained by the State Divisionof Highways. Off-site freeway drains, invertedsiphons, and pumping plants are generallymaintained by the City Bureau of Sanitation underagreement with the State.

G 023 LOS ANGELES COUNTY FLOODCONTROL DISTRICT

The Los Angeles County Flood Control District(LACFCD) is a legal entity established by the Stateto allow the collection of taxes for the constructionof drainage facilities. The primary function ofLACFCD is the improvement and maintenance ofmajor watercourses, the cost of which is beyond thefinancial capability of municipal agencies.The Comprehensive Plan-Control and

Conservation of Flood Waters (Figure G 023)delineatesthe major watercourses for which the LACFCD isresponsible.

The LACFCD also provides additional drainagerelief by constructing trunk storm drains which serveas outlets for local drains. The local agenciescoordinate their drainage needs through the LACFCDfor a District-wide Bond Issue Program.

The City of Los Angeles, as a local agency,proposes and controls the design of its own projectsthrough the use of city employees or privateengineers. The LACFCD lets construction contractsfor these projects and maintains the facilities. The CityCouncil has agreed to quitclaim all City drainageeasements under the jurisdiction of the Department ofPublic Works to the LACFCD as required for theseprojects.

LACFCD projects are designed to their standards,which are not covered in this manual. However, Cityrunoff criteria and methods are used in the design.

G 024 CITY OF LOS ANGELES

Storm drains in the City of Los Angeles, otherthan those by LACFCD, are financed by Gas TaxFunds, Capital Improvement Funds ( Section G 030),by Assessment (Section G 040), or by PrivateDevelopment (Section G 050).

The drains financed under Capital Improvementprovisions and Assessment proceedings are usuallyconstructed in conjunction with street improvements.Storm drains provided by private development aregenerally those required from tracts. The City hasdeveloped a Master Plan of Drainage, coordinatedwith the LACFCD Comprehensive Plan, whichdelineates the watercourses requiring improvement.

If private development is in an establisheddrainage district, such as exists in the San FernandoValley area, the developer is required to deposit anacreage fee in a special fund. As these fees becomeavailable, the City designs and constructs the stormdrains. In other areas of the City, the construction ofstorm drains is required as part of the development, asoutlined in Section G 050.

G 025 OTHER AGENCIES The City of LosAngeles is bordered by many local agencies withsimilar drainage problems.


G 030June, 1973

Financial savings are very often realized bycooperative participation in common construction.Therefore, many storm drain designs are submittedto the City for review and comment prior toconstruction. Such review is made by the Cityengineering district of jurisdiction.

For projects built in the City but financed byanother agency, such as the construction of drainswith street improvements by the County Road

Department, the designer generally reviews the plansfor accuracy of substructures, compliance to Citystandards, adequacy of facilities, and coordinationwith adjacent construction, either existing orproposed. For projects in a bordering agency usingCity drainage facilities as an outlet, the designerchecks that the outlet drain capacity is not exceededand that diversion does not take place

G 030 CAPITAL IMPROVEMENT PROJECTSCapital Improvement Projects are those projects

initiated by the City to eliminate public hazards orto provide public service. Storm drains areindependently financed by Capital ImprovementFunds, although a majority of the drains areconstructed in conjunction with streetimprovements. A storm drain Capital ImprovementProject is generally considered necessary whendamage, periodic flooding, etc., call attention to adrainage problem. These projects are requested bythe District Office in the order of preference forfinancing. For Capital Improvement procedures,refer to the Operations and Control Manual. MostCapital Improvement Projects are limited toimprovements providing more than local benefit.However, if hazardous conditions exist which couldresult in liability for the City, drainage facilities oflocal benefit may be included with the CapitalImprovement Project. The designer must use goodjudgment in his evaluation of the existing hazard.

G 031 FINANCING

The various sources of funds available to theCity Council to finance Capital ImprovementProjects, together with a short summary of theirlimitations for storm drain use. are as follows:

G 031.1 State Gas Tax Fund: The City of LosAngeles and other Cities in the State share anamount-per-gallon gas tax fund proportionedaccording to population, or vehicle registration andassessed valuation. This money is available forconstruction, R/W acquisition, and maintenance oncity streets qualifying under the Select System ofstreets. State policy restricts the use of these fundsto these drainage facilities which directly benefitvehicular traffic in amounts as specified below.

Sections 2106 (1.04 ¢ ) and 2107 (.725 ¢ ) of theStreets and Highways Code and the Office of the

State Controller Guidelines Relating to Gas TaxExpenditures on Streets and Roads (March, 1971)state that this gas tax money is available for suchstreet and road drainage work as:

a) complete reconstructions or additions toculverts

b) installations or extensions of underdrainsc) extensions of existing culverts and drains and

replacements of headwalls.

A city may not use moneys to construct facilitieswhich are required to drain roads and streets not in theselect system. It follows that a drain located on theselect system which is constructed larger than wouldbe necessary to drain the select system, for thepurpose of carrying other than select system drainage,must be financed in part with moneys not restricted tothe select system. Also, any drain located on theselect system that carries only drainage water fromroads or streets not in the select system must befinanced with moneys which are not restricted toselect system construction and rights of way.However, when existing drainage facilities requirelowering or relocating soley by reason of constructionor improvement of a select system street or road, thecost of such lowering or relocating will be 100%eligible for financing with select system moneysirrespective of the source of the drainage watercarried. The costs of any betterments involved in suchreconstructed or relocated drainage facility will beparticipating to the extent of benefit to the selectsystem.

Each city shall determine for each constructionproject on its select system which includes drainagefacilities, the costs which are properly chargeableagainst Section 2106 moneys. For this purpose thoseportions of the drainage system listed below may befinanced entirely with such moneys:

l. Cross culverts regardless of angle of crossing.2. Storm drains, culverts, or drainage channels


G 023June, 1969

which are required to be constructed orreconstructed by improvement of the roadway of theselect system street or roadway.

3. Longitudinal storm drains or otherlongitudinal culverts, including manholes, locatedwithin the select system rights of way and whichdrain the select system only.

4. Cross or longitudinal gutters atintersections.

5. Catch basins and related pipes.The term catch basin shall include outlet

structures or curb openings. Eligible catch basinsmust be located within the select system rights ofway, or as close to the curb return joining the selectsystem as practicable considering the location ofobstructions and/or hydraulic considerations.

Longitudinal select system drains which areinterconnected with longitudinal drains from roadsand streets not on the select system and which aredesigned to convey both select system drainage andother than select system drainage may be jointlyfinanced with select system construction moneysand other moneys in the same ratio as the quantityof water from each of the two systems it is designedto convey. Longitudinal drains do not have to bewithin the select system rights of way but may belocated a reasonable distance therefrom. If it can beshown that such a drain will convey select systemdrainage water in a manner as economically as if itwere located within the select system rights of wayit is eligible for financing with select systemconstruction moneys in the same ratio as set forthabove.

Outfalls and connections to other drainagesystems for the purpose of disposing of selectsystem drainage concentrations are eligible forfinancing in the same manner as set forth above.

Each city which expends Section 2106 moneysto finance the construction of drainage facilitiesshall keep records for a period of at least three yearsafter the end of the fiscal year of the expenditure,showing how it calculated or otherwise determinedthe amount of such moneys that were eligible tofinance such facilities. Such records shall be madeavailable to the auditors of the State Controller orother representatives of the State who are authorizedto examine them for the purpose of verifying thatthe restricted moneys were used only to financefacilities or portions thereof which drain the selectsystem.

Gas Tax replacement moneys are available also

for such maintenance work as reshaping drainagechannels and side slopes, restoring erosion control,cleaning culverts and drains, and repairingunderdrains, culverts, and drains.

G 031.2 County Gas Tax Fund: Money from theLos Angeles County Subventions and Grants Fundsare available for use by the City for drainage facilities,provided essentially the same requirements inSubsection G 031.1 above are met.

G 031.3 Permanent Improvement Fund: This isan amount of money per $100 of assessed value oftaxable property which is set aside by the City foracquisition of land or right of way and forconstruction of public works improvements with anestimated life of ten or more years. PermanentImprovement funds are usually used to financeprojects or construction not eligible for gas tax fundsor financed by assessment or private development.Storm drain projects, either alone or in conjunctionwith street improvements, may qualify for financingunder this fund.

G 031.4 Other Funds: Other sources of revenueare the General Fund, the Subventions and GrantsFund, and the State Grade Separation Fund. TheGeneral Fund, which contains revenues notappropriated for other purposes, is often appropriatedup to $5000 (by the CAO without City Councilapproval on previously approved projects) for stormdrain purposes. The Subventions and Grants Fundconsists of money allocated to the City from the Stateor County for specified purposes, either in the form ofsubventions, to which are attached restrictions on theiruse, or grants which generally have no restrictions.This fund is often used to acquire easements for stormdrain projects. The Streets and Highways Code statesthe limitations on the use of the State GradeSeparation Fund for storm drain purposes.

G 032 PREPARATION OF CIP REQUESTThe District or Division Engineer is responsible forinitiating a Capital Improvement Project (CIP) in hisdistrict. Ordinarily, the storm drain designer makes aPreliminary Study (Section G 180) to acquire the datanecessary for a CIP request. This data is presented ona CAO-39 form a plan location sketch, and a class “B”cost estimate and submitted to the CoordinatingDivision. Refer to the Operations and Control Manualfor the requirements and procedures necessary forrequesting a Capital Improvement Project.


G 033June, 1969

The District Office should review all CIP’sannually to update their cost and order ofpreference. Changes in field conditions whichappreciably change the scope or the cost of a projectrequire the submittal of a revised CAO-39. Projectswhose change in cost is less than 10% (or asdirected by the Advance Planning Section ofCoordinating Division) need not be revised.However, the order of preference for all projectsshould be submitted by the Districts every year.

G 033 COST ESTIMATE CLASSIFICATION

Cost Estimates for Capital ImprovementProjects have been defined and classified asfollows:

Tentative Estimate ‘ Class “C”: This class ofestimate is intended to show order of magnitudeonly and is subject to major revision. It is not to beused as a basis for fund appropriation. This estimateis based on general knowledge of the project withregard to location, limits, width of right of way,and other known physical character-

istics, with due consideration given to similar projectsin the same area.

Appropriation Estimate-Class “B”: An estimateof this class is used as the basis for fund appropriation.It is based on specific, detailed knowledge obtained byfield investigations and studies. Sufficientconsideration should be given to this estimate toreasonably assure the construction of the project.

Final Estimate-Class “A”: This class of estimateis the final summation of costs by the Utility andEstimating Division based on completed constructionplans. It forms the basis for determining theconstruction cost of the project. If this estimateindicates that additional funds will be required, aprompt report should be made to the Board of PublicWorks.

The design engineer is urged to consult the Utilityand Estimating Division for verification of unit costs.For comparative costs used in studies orinvestigations, the LACFCD Cost and QuantityManual (latest revision) may be used.

G 040 ASSESSMENT PROJECTSAssessment projects are generally financed

under the 1911 Act of the State Street andHighways Code or the 1941 City Ordinance. Theyare usually initiated by petition from propertyowners, and paid for by the assessment of theproperty benefiting. The design engineer is referredto the Operations and Control Manual forassessment procedures (Chapter C 400).

Assessment projects are designed in the sameorder as the petitions are filed, unless otherwisedirected by the City Council. Approval of thepetition by the City Council is required beforedesign is begun.

G 041 PRELIMINARY PROCEDURES

Prior to design, many procedures are requiredfor Assessment Projects which are initiated by thedesign office. These are outlined in detail inAssessment Project Procedures (Section E 810) ofthe Street Design Manual. Ordinarily, the designermakes a feasibility study and prepares a class “C”tentative cost estimate. Based on this study, aRecommendation Report is prepared which includesthe feasibility and scope of the

project, the Planning Commission recommendation,the tentative cost estimate, a request for authorizationfor Right of Way acquisition (if required), and arequest for allocation of public funds (if required), forwhich a CAO-39 form is used. This report is sent tothe Assessment Section of the Coordinating Divisiontogether with the petition signatures and sketch. Ifanother Department is involved in the project, a jointreport is prepared.

G 042 DESIGN CONSIDERATIONS

In the design of storm drain assessment projects,the designer must check that the construction iseligible for financing under assessment proceedings.For example, the relocation of utilities which haveprior rights cannot be financed by assessment. Duecare must be taken to restrict the drainage design tothat which benefits only the local area underconsideration.

Most drains financed by assessment are thoseincidental to street improvements. Where storm drainsare included in a street improvement assessmentdistrict and the extent of drainage facilities


G 043June, 1973

required are more than normal minimum catch basinand connection laterals necessary to make the streetimprovement functional, the cost may be defrayedby City public funds. If financing by public funds isnot provided and a main line or lateral is requiredfor the project, a drainage assessment district shouldbe established.

Since the cost of the improvement is paid byproperty owners who could protest the project out,the expense of the project is of prime importance.The designer should limit the drains to the veryminimum required but should not sacrifice designstandards.

G 043 DRAINAGE ASSESSMENT DISTRICT

Whenever a storm drain main line or lateral isfinanced by assessment, either as a separate projector in conjunction with a street improvement, thedesign office must provide the information bywhich the Bureau of Assessment distributes the

cost among the property owners benefiting from theproject. Any change of conditions resulting from theproject which improves or alleviates the drainageeither upstream or downstream from the project maybe deemed a benefit, and the property can beincluded within the drainage district boundary.

A separate map of the watershed boundary andthe area of each individual assessment parceltributary to or benefiting from the storm drain and adiscussion of any engineering factors that influencebenefit or responsibility for cost in the assessmentdistrict must be furnished with the memo oftransmittal to the Coordinating Division. If asubstantial portion of the tributary area is outside ofthe assessment boundary, consideration must begiven to either expanding the boundary orappropriating public funds to help pay for theimprovement.

G 050 PRIVATE DEVELOPMENT PROJECTSThe public drains acquired as a result of private

development are those financed and constructed bya landowner in improving his property. The cityrequires storm drains in two basic types of privatedevelopment, the subdivision and the lot-splitordinance.

The city design engineer must familiarizehimself with the drainage problems of each area,since he represents the city in the solution of suchproblems. It is recommended that the city designerconfer with and advise the private engineer insolving the more difficult drainage problems.The procedures for processing subdivisions will becovered in the Subdivisions and Dedications portionof the manual.

G 051 SUBDIVISIONSA subdivision generally refers to any real

property, improved or not, which is divided for thepurpose of sale or lease into five or more parcelswithin any one-year period. (The exceptions arenoted in Section 11535 of the Business andProfessions Code.)

The State Subdivision Map Act of the Businessand Professions Code provides the City of LosAngeles the authority to regulate and control thedesign and improvement of subdivisions. Cityrequirements for the proper control of drainage anderosion of subdivisions are outlined in Sections17.02, 61.02, and 91.30 of the Municipal Code. The

City Engineer’s drainage and erosion controlrequirements for the approval of subdivisions arespecified in the following subsections.

G 051.1 Drainage Policy for Approval ofSubdivisions: At the time application is made forsubdivision of any area within the City of LosAngeles, the City Engineer may require thesubdivider to submit a grading plan showing theexisting topography of the area prior to developmentand the proposed topography after development. Theplan shall include provisions for controlling all stormrunoff within the proposed subdivision, and fordischarging the storm runoff from the subdivision insuch a manner as to protect the upper and lowerproperties from damage or nuisance resulting fromsuch discharge. The computed storm runoff from thesubdivision shall include the runoff from the entirearea tributary to the subdivision, and shall be basedon the ultimate development of the area as shown onthe Master Plan of Land Use. Where such a gradingplan is required, the acceptance of the tract forrecordation will require the approval of said plan bythe City Engineer and the Department of Buildingand Safety, and the filing of a sufficient surety orcash bond guaranteeing the construction of thedrainage facilities indicated on said approved plan,and the payment of fees pursuant to the scheduledescribed herein.


G 051.2June, 1969

G 051.2 Definitions:a. Runoff shall refer to the quantity or

quantities of water as determined by application ofChapter G 200, Hydrologic Design, as adopted andas currently used by the Bureau of Engineering mthe design of all drainage facilities. It shall includesurface runoff and runoff in storm drains and naturalchannels.

b. Surface runoff is that portion of the runoffflowing across the surface of the land and notconfined to natural channels or storm drains.

c. Runoff from the tract shall include all runofffrom the area tributary to the tract as well as fromthe tract. It shall include all runoff naturally flowingto, through, and from the tract.

d. Drainage facility or drainage facilities shallinclude all means of intercepting, conveying, orstoring storm water, including natural watercourses,improved drainage channels, retarding basins,closed conduits or pipes, and flood protectivefacilities.

e. Storm drain or storm drains shall meanpermanent storm drains and shall, in general, becovered conduits or lined open ditches.

G 051.3 Causes for Withholding Approval:Approval of a subdivision shall be withheld if, inthe opinion of the City Engineer, one or more of thefollowing conditions exist:

a. The area is subject to flooding duringrainstorms, which will cause conditions dangerousto persons or structures.

b. There is no on-site drainage facility availablewhich is adequate to convey the computed runofffrom the tract without causing said drainage facilityto overflow to the extent that damage to public orprivately-owned property or injury to persons mightresult.

c. Runoff from the tract cannot practicably beconveyed to an adequate off-site drainage facility.

d. Excess runoff resulting from the subdivisioncannot be retained within the subdivision.

G 051.4 Means for Providing AdequateFacilities: The methods considered acceptable bythe City Engineer to prevent damage to public andprivately-owned property, or injury to persons,

include, but are not necessarily limited to, thefollowing:

a. Collection in the public street system of allrunoff from the tract, limited to such quantities aswill be unobjectionable to the use of said streets. Thedepth of flow during a storm of 10 year frequencyshall not exceed curb height (usually 8 inches) wherethe longitudinal slope is 2% or less. When the streetslope exceeds 2%, the depth of flow and themaximum allowable street flow shall be reduced sothat the momentum of the street flow (QV/g) doesnot exceed the value of the momentum for flow atcurb depth on a slope of 2%, Q = flow in cfs, V =velocity in fps, and g = acceleration of gravity (32.2fps2). The computed values for the maximumallowable momentum for standard street widths andthe method of computation are shown in OfficeStandard No. 118. In computing depth of flow incurved streets, the superelevation of the water surfaceshall be taken into account. (See Section G 111.)

b. Construction of storm drains to intercept all ofthe runoff and convey it to a suitable point ofdisposal into a natural watercourse or adequatedrainage system whenever the limiting depth of flowis exceeded. These storm drain systems shall meetthe following requirements:

1. In areas without sumps, storm drains shallbe designed to remove all runoff from a storm of 10-year frequency.

2. In sump areas, storm drains shall bedesigned to remove all runoff from a storm of 50year frequency.

3. Storm drains shall be of sufficient size in allcases to prevent flooding of building sites during astorm of 50-year frequency.

4. On side-hill streets, the maximum depth ofwater during a 50-year storm shall be curb heightexcept as modified in Subsection G 051.4a above.

c. Reduction in peak rate of discharge ofrunoff from the tract, so as not to exceed the safe rateof discharge for which storm drain facilities areavailable, by:

1. Limiting the impervious areas of theproposed subdivision by increasing lot sizes or byother means.

2. Construction of retarding basins or otherfacilities to store excess runoff from the tract untilsaid runoff can be discharged safely.


G 051.5June, 1969

G 051.5 Additional Requirements:

In order to accomplish the above desired resultsin connection with the subdivision of any area,drainage easements shall be provided for all stormdrain facilities which are not located in present orproposed public streets or alleys. Detailedengineering plans (see Subsection G 051.7) shall beprepared for the approval of the City Engineer andthe improvements shown on these plans shall beconstructed under proper permit from the City.

All cut and fill slopes on private propertyabutting public property shall conform to therequirements for Grading, Excavations, and Fills asset forth in Chapter IX, Article I, Division 30, of theMunicipal Code as administered by the Departmentof Building and Safety. The general provisions ofthis ordinance are:

a. Cut and fill slopes shall be a maximum of 2horizontal to 1 vertical unless otherwise approvedby the Department of Building and Safety and theCity Engineer.

b. Drainage benches shall be constructed on allcut and fill slopes at vertical intervals of 25 feet.Minimum width of drainage benches shall be 8 feet.

c. Devices acceptable to the City Engineershall be constructed to reduce erosive velocitieswhen runoff is discharged into natural ortemporarily improved channels.

The outlet portion of drains discharging intonatural watercourses and the portion of drains inpublic streets and easements are under thejurisdiction of the Department of Public Works andmust be approved by said Department.

G 051.6 Maintenance of Basins: Pursuant to apolicy of the Board of Public Works adopted May24, 1967, City forces shall perform the requiredmaintenance of all retarding basins and debrisbasins within the City except those retarding basinsapproved prior to said date and pursuant to a suretybond guaranteeing maintenance by the owner ordeveloper. The policy regarding maintenance byCity forces includes the following regulations:

a. All debris basins shall be exempt frompayment of a fee for maintenance.

b. The owner or developer of property subjectto a division of land action requiring the construc-

tion of a retarding basin shall pay a fee to the City asset forth in the table below to defray the cost ofmaintenance of said retarding basin by City forces.

‘

Subject to reduction.

c. Upon acceptance of a prorated fee from theowner or developer, the City shall assume theresponsibility for maintenance of retarding basinspreviously approved pursuant to a surety bonds andthe bond shall be exonerated.

d. The fee established for maintenance of newretarding basins shall be based upon a period of fiveyears. In the event it is determined by the CityEngineer that the basin is no longer required prior toexpiration of the five-year period, a partial refund, inaccordance with the Schedule of Fees, may be madeto the payer upon his request.

G 051.7 Submittals for Approval: The planssubmitted to the City for approval are the tract map,the grading plan, the construction plans, and ifrequired, the erosion control plan. The storm drainplans should be coordinated with the street and sewerplans to prevent conflict in design.

The plans are submitted to the District orDivision of jurisdiction for checking prior toapproval by the City Engineer.

Prior to notifying the Street Opening and WideningDivision that the final tract map is satisfactory forrecording, it shall be the responsibility of theappropriate District or Division to verify with theBureau of Right of Way and Land that:

1. The off-site easements have been acquired byseparate instruments, or

SCHEDULE OF FEE(Retarding Basin)

Period of *Charges perResponsibility Cubic Yard

in Years Basin VolumeNew Basin Five $1.00Existing Basinor ProratedNew Basin More than four $1.00 Three to four $1.00Basin Two to three $0.75 One to Two $0.50 Less than one $0.25


G 051.71June, 1969

2. That sufficient funds have been depositedby the subdivider to fully guarantee acquisition ofthe off-site easement and that its acquisition isassured.

The grading plan must be approved by both theCity Engineer and the Department of Building andSafety.

In order that the Bureau of Sanitation canmaintain a current schedule of maintenance, eachDistrict and Division shall notify the Street Openingand Widening Division, Bond Section, in writingwhenever a new debris or retarding basin isapproved for acceptance so this information may betransmitted to said Bureau.

G 051.71 Tract Map: The tract map is a planof the proposed subdivision showing the sizes andrelative locations of lots, streets, and easements withproper descriptions for legal documentation. Thestorm drain designer shall check for the adequatelocation, size, and description of the easementsrequired for drainage facilities. Should drains berequired outside of the tract boundary, thesubdivider shall provide for the proper easementseither by including the easements within the tractboundary or by separate instrument. The easementcall-out, properly identifying the area referred to, iseasement to the City of Los Angeles for drainagepurposes. Call-outs dedicating property “to the Cityof Los Angeles in fee simple” must be accompaniedby a note delineating the intended use of theproperty by the City.

G 051.72 Grading Plan: The grading planindicates the changes to be made in the existingground surface for the construction of the proposedimprovements. It shows the topography andcontours of the area as existing before development;the proposed contours after development; the planlayout with identification of lots, streets, andeasements; and the general provisions for thecontrol of surface runoff in the streets, in easements,and in watercourses. The designer shall review theproposed drainage provisions to satisfy himself as totheir adequacy, alignment, and proper use inaccordance with City standards. He should payparticular attention to the possibility of diversioncaused by the proposed improvement.

Drainage facilities constructed on private propertyand maintained by the property owner are

private drains. Whenever such drains enter the streetor drainage easement, however, they are publicfacilities maintained by City forces. Such drains mayoutlet into the street, provided that no hazard to thepublic is created and that the portion within the streetis an approved conduit. Each lot shall drain directlyto the street gutter or public drainage facility bymeans of a driveway or other approved facility.When no public drainage facilities are directlyavailable and the street grade is too steep to containthe lot drainage within the driveway area, adequateprotective measures shall be provided to protect theadjacent parkway from damage by erosion.

Cut and fill slopes adjoining streets, drainagechannels, or other public facilities are subject to therequirements of the City Engineer. The requirementsfor slope stability, drainage facilities, and gradingcontrols are given in Section G 150. The GradingPlan Notes given in Section G 151 must be shown onall such plans. This plan is not a permanent recordbut requires the approval of the Division or DistrictEngineer.

G 051.73 Storm Drain Plans: Privatelydesigned plans including profiles and details for theconstruction of drainage facilities in subdivisionsshall be identical to city-designed storm drain plansexcept for the signature and registration number ofthe responsible engineer on the title sheet. Sincethese plans become permanent city records, theyshould be thoroughly checked by the City designer.All criteria, standards, and requirements delineated inthe design sections of this manual are applicable tothese plans.

G 051.74 Erosion Control Plans: The CityMunicipal Code establishes the period betweenDecember 1 and April 15 as the rainy season, duringwhich heavy rainfall normally occurs in the City.Subdivision grading work during this period shallincorporate temporary erosion control devices wherethe City determines that such work may endangerpublic health or safety. Plans of erosion controldevices shall be submitted to the Bureau ofEngineering and design approval obtained not laterthan September 15 of the coming rainy season. Alltemporary erosion control devices shall be installednot later than December 1. Desilting basins shall beinstalled not later than October 15.


G 051.8June, 1969

An erosion control plan is basically a gradingplan over which erosion control measures aresuperimposed. This plan is not a permanent recordbut requires the approval of the Division or DistrictEngineer. The city designer shall check that the planmeets City requirements on placing sandbags,constructing desilting basins, and other measures (asgiven in Section G 150) deemed necessary tocontrol the deposit of silt and debris onto Citystreets or natural watercourses. The Erosion ControlPlan Notes (given in Section G 153) must be shownon all such plans.

G 051.8 Flood Hazard Report: The City ofLos Angeles is responsible for furnishing FloodHazard Reports to the owner of a tract or to thepublic upon request. The Opening and WideningDivision requests such a report, which designatesthe extent and frequency of flood hazard, from thedesign office.

To indicate the extent of flood hazard, the termsand their definitions used in this report are asfollows:

Inundation indicates ponded water or water inmotion, of sufficient depth to damage property dueto the mere presence of water or to the deposition ofsilt.

Flood hazard indicates overflow water havingsufficient velocity to transport and deposit debris, toscour the surface soil, or to dislodge or damagebuildings. It also indicates erosion of watercoursebanks.

Possible flood hazard indicates possibleextension of areas denoted as subject to floodhazard, also the uncertainty of degree or extent ofbank erosion.

Sheet overflow indicates water of minor depth,either quiescent or flowing, at velocities less thanthose necessary to produce serious scour. This typeof overflow is considered a nuisance rather than amenace to the property affected.

Ponding of local storm water indicates standingwater in local depressions. This is distinguishedfrom sheet overflow by the fact that it originates onor in the vicinity of the property and is unable toreach a street or drainage course because of thecondition of the ground surface.

To indicate the frequency with which thesevarious hazards may occur, the following terms andtheir definitions are used:

Frequent: This term is used when a conditioncan occur at intervals of ten years or less whenaveraged over a long period of time. Several of theseconditions may occur in a single decade or there maybe no such occurrence for a period of time muchgreater than 10 years.

Infrequent: This term is used to denote anaverage interval between occurrences of more than10 years.

Remote: This term is used when the occurrenceis dependent upon conditions which do not lendthemselves to frequency analysis, such as thediversion of a stream from its present bed due tobreach of channel bank, deposition of debris, or thepresence of other channel obstructions.

G 052 LOT SPLITS AND SINGLE LOTSFor development of lot splits (a division of land ofless than five lots) or single lots, the City Engineerrequires the construction of drainage facilities onland utilized for natural drainage. Whatever theexisting conditions, the design engineer mustconsider the liabilities outlined in Section G 012.

G 052.1 Drainage Control: The control ofdrainage on lot splits or single lot developments istwo-fold:

a. If a watercourse exists, the property ownermust acquire a permit to do work in or adjacent to thewatercourse (Sections 64.07 to 64.10 inclusive ofOrdinance No. 77.000).

b. If the property is located in an inundated area,the property owner must acquire an inundationclearance prior to construction to determine whetherhis property is subject to damage from inundation orflood hazard (as defined in Subsection G 051.8).

G 052.2 Watercourse Considerations: If theproposed improvement is only a partialencroachment on a watercourse with no intent todevelop it, the design engineer will refer to theconsiderations outlined in Section G 070.


G 052.3June, 1969

However, if the encroachment is such as towarrant the total or partial improvement of thewatercourse, the design engineer must consider theimprovement as a public facility requiringconstruction under permit in accordance with plansapproved by the City. The dedication of a publiceasement for drainage purposes may be requiredonly if the improvement is to be a part of a citystorm drain system. The construction shall consistof a storm drain conduit and appurtenant facilities of50-year storm frequency, based on ultimatedevelopment of the watershed in accordance withCity standards. No private buildings should beallowed over the conduit or in the easement withoutthe specific approval of the City. All surfacedrainage should enter the storm drain throughapproved inlets.

G 052.3 Inundation Report: Wheneverproperty is subject to possible damage byinundation or flood waters, the Department ofBuilding and safety requests an Inundation Report(Figure G 052.3) from the engineering district ofjurisdiction prior to issuing a building permit. Thisreport reflects the design engineer’s evaluation ofthe property in relation to surface runoff or floodwaters, to determine:

a. The extent and frequency of flood hazardinvolved;

b. The possible corrective measures to reducethe hazard; and

c. Whether construction should berecommended.

Unless a watercourse is involved, this report isonly a recommendation to the Department ofBuilding and Safety, which is responsible fordetermining and enforcing the final conditions. Theengineer circles the appropriate condition, makesany necessary remarks on the form, and completesthe stamp on the back of the building permitapplication. One copy of the form is retained by theclearing office, Bureau of Public Works, and theother copy is returned to the Grading Division,Department of Building and Safety, with the plansand permit.

Flood hazards may be caused by ponding or bysurface flow. Factors to be considered are the amountand concentration of water, its source, possible reliefby use of existing drainage facilities, the amount ofproperty affected, the depth of flow or ponding, thevelocity and scouring effect, the depositing of debrisor mud, the length of ponding time, and finally, thetotal estimated damage and frequency of occurrence.All damages resulting from storms of 50-yearfrequency or less will be considered. Records ofexisting storm drain projects, drainage maps, andprevious inundation reports in the vicinity areinvaluable aids in this determination. If possible, it isrecommended that for less obvious situations, a jointfield trip with the Department of Building and Safetygrading inspector be arranged to discuss the effectthat the contemplated grading will have on the properdrainage of the property.

The corrective measures considered to reduce thehazard are those deemed necessary for the protectionof life and property. Measures such as filling theproperty to be completely clear of inundation from a50-year storm may not require a waiver of damagesfrom flood waters by the property owner. If,however, a minimum floor elevation is recommended(where surface flow cannot be blocked) to get abovethe high water level, leaving other portions of theproperty or the access to the property inundated, thena waiver of damages releasing the City from liabilityis required from the property owner.

Past practice has been to allow the propertyowner to build, if at all possible, provided measurescan be taken to keep him reasonably free from flooddamages and if he is made aware of the risk by therequiring of a waiver of damages. The engineershould not hesitate to recommend againstconstruction, should a risk for which no correctivemeasures can be taken endanger life.

The engineer is referred to Subsection G 051.8for the terms used in the report. The extent andfrequency of the hazard and the recommendedcorrective measures to be taken are shown underRemarks on the report. The Department of Buildingand Safety is responsible for acquiring necessarywaivers.


G 060June, 1973

G 060 EASEMENTSG 061 DEFINITION

An easement to the City of Los Angeles is adocumented legal right obtained by the City from aproperty owner, allowing the City to enter theproperty for a specified purpose. It does not affectownership of property. To have an easement fordrainage purposes usually means to have the rightsof ingress and egress for the construction andmaintenance of drainage facilities. The specified useof the easement may not be changed without furthernegotiation with the property owner. Generallyspeaking, the holder of an easement must use theeasement in a reasonable manner. (See EasementStandards, Section G 122.)

For more information on the acquisition ofproperty, refer to Fundamentals of Real Property forStreet Design Purposes in the Street Design Manual(Section E 050).

G 062 POLICYThe City of Los Angeles requires that all public

drainage facilities be constructed either on Cityproperty or in an easement for drainage purposes.Such an easement is usually permanent unlessquitclaimed by the City.

G 063 TYPES OF EASEMENTSG 063.1 Temporary Easements: Temporary

easements are those acquired for a limited period oftime, the length of which is usually determined bythe amount of time required to accomplish work.Types of temporary easements are constructioneasements and some slope easements. Aconstruction easement gives the City the right tooccupy private property for working operations ofthe contractor. A temporary slope easement givesthe City the right to occupy private property tograde slopes. These easements are usually acquiredfor the duration of construction. After the specifiedperiod of time has elapsed, all rights conferred by atemporary easement revert to the property owner.

G 063.2 Slope Easements: Slope easementsare usually permanent easements obtained for theconstruction and maintenance of dirt slopes adjacentto public property or easements. If only a temporaryeasement were desired for the construction of a dirtslope, a temporary slope easement would beobtained. The maintenance of the

slope after completion of construction is theobligation of the party which has the easement or, ifno easement exists, the owner of the property.

G 063.3 Combined Easements: A combinedeasement is usually obtained for more than onepurpose; e.g., an easement for sewer and drainagepurposes. It is not practical to combine easements forpurposes under different City departmentaljurisdictions.

Easements obtained by different departments of theCity for different purposes may overlap. Also, twoagencies may have the same rights in the sameeasement. These and similar types of easements arenot usually considered combined.

G 063.4 Future Easements: A future easementis an irrevocable offer of rights for a specifiedpurpose, made by a property owner to agovernmental agency. It prevents any use of theproperty within the easement which would becontrary to this purpose, even though the agency hasnot yet accepted the offer. Although it may beaccepted at any time, the offer is usually not accepteduntil just prior to construction. A future easement isusually not considered unless construction of publicfacilities is intended.

G 063.5 Rights of Entry: A right of entry, likean easement, is a documented legal right to enterprivate property for a specified purpose. It isgenerally used to acquire rights of ingress and egressonly, or for construction of minor or temporarynature of short duration. Its use may be preferableover an easement because it is generally more easilyacquired and is less costly. The Bureau of Right ofWay and Land usually determines in theirnegotiations whether the use of a Right of Entry isadvisable.

G 064 WORK IN A DRAINAGE EASEMENTThe City of Los Angeles has an obligation to

protect the public from damages caused by misuse ofdrainage facilities under its jurisdiction. The Citymay accomplish this by invoking easement rights toprotect its drainage facilities. Control of land use ineasements is maintained by requiring the propertyowner to apply for a construction permit.

Figure G 064 shows the standard application formwhich the property owner must fill out


G 065June, 1973

to obtain permission to do work in a City drainageeasement. The engineer must review the applicationto determine the type, extent, and location of thework contemplated. If a structural check of theproposed work is needed, a plan must be submittedwith the application. The engineer should review thearea in the field and recommend what the Cityrequires to protect its drainage facilities. Theprocessing of this application and the permitrequired is covered in the Operations and ControlManual.

The prime concern of the engineer in reviewingthe application is the protection of existing Citydrainage facilities. Work is usually allowed in adrainage easement provided the construction or useof the easement does not undermine, overload,obstruct, or otherwise damage or incapacitate thestorm drain. If-the work imposes loads or conditionsfor which the storm drain was not designed, theengineer should require the following:

a. The alignment and depth of a covered stormdrain shall be determined in the field,

b. the storm drain structures shall bestrengthened to withstand the loads or protectedagainst conditions imposed by the work, and

c. manholes or other accesses blocked by thework shall be remodeled or relocated.The engineer shall transmit the proposedconstruction plans affecting the storm drain to theStructural Engineering Division for structuralreview and approval.

In addition to the above requirements, theengineer may require that the City be held harmlessfrom any damages resulting from the work in theeasement. After evaluating how the proposed workaffects the existing drainage facilities, the engineermust use good judgment in determining when torequire a waiver. Generally, a waiver of damages(Figure G 064A with Figures G 064H, Corporation,or G 064I, Private) is required from a propertyowner for any construction in a drainage easementin which drainage facilities exist. The protectiongranted to the City by the waiver is listed in items 1to 5 of Figure G 064A. This waiver should beapplied to protect City drains which may bedamaged by the work and/or to protect the Cityfrom liability resulting from this damage.

The approved procedure for processingWaivers of Damages is outlinedin the Engineering Form

3.685C (Figures G064J and K). This document isdistributed with the waiver and includes instructionsto both the applicant and City personnel. Thisprocedure shall be followed to protect both theapplicant and the City.

The six modifications shown below are to beused as a supplement to the original Waiver ofDamages (Form 3.685). The information contained ineach modification is standardized and has beenapproved for use by the City Attorney. Whennecessary, the appropriate modification should beselected for the waiver used and typed on the originalwaiver form as shown on the samples, Figures G064B , C, D, E, F, and G.

The modifications are:Modification 2

Watercourse (see Section G 070)Modification 3

City Easement and WatercourseModification 4

LACFCD EasementModification 5

City and LACFCD EasementModification 6

LACFCD Easement and WatercourseModification 7

City and LACFCD Easement and WatercourseIf an application is made for temporary use of adrainage easement (such as grading or crossing ofequipment over a drain capable of withstanding theload), the engineer should require a bond (in lieu of awaiver) to cover the cost of repair of any damages tothe drain which may be incurred thereby. If nodrainage facilities or watercourse exist in a drainageeasement, no waiver or bond need be required.However, a revocable permit should be issued.

G 065 COMMON RIGHT OF WAY TERMSAdverse Possession: An easement may be

created by a use in a manner adverse to the exerciseof the fee owner’s rights for a continuous period offive or more years.

Condemnation: The exercise of the power ofEminent Domain (Subsection G 012.22).

Damages, Actual: Value of the property taken;e.g., square-foot value of a parking lot.

Damages, Severance: Value of the damages byvirtue of a taking of the remaining property; e.g., lossin value of a business building by reduction ofparking area.


G 070June, 1969

Easement: A right or interest in the land ofanother which entitles the holder thereof to somespecific use, privilege, or benefit out of or over saidland.

Fee Title: The highest type of interest a personcan have in land. It is potentially of indefiniteduration, freely transferable, and inheritable.

Grant Deed: Conveys the fee title to the land.

Lease: The use of property given to another fora stated period of time for a consideration andobligation to perform by both parties for the statedtime.

License: A personal, revocable, and non-assignable permission or authority to enter uponland of another for a particular purpose.

Permit: A temporary, revocable, and non-transferable license which gives one permission to dosomething without which one would be a trespasser.

Prescriptive Rights: A public easement may becreated without formal documentation by permissiveacts of the owner for a period of five or more years(e.g., repaving a sidewalk area and allowing thepublic to use the walk without obstruction).

Quitclaim Deed: An easement (or interest ofuncertain validity) may be extinguished by a releasein favor of the owner by the easement or interestholder.

Rent: The use of property by one other than theowner on a period-to-period basis (e.g., month-to-month) for a consideration terminable at the end ofany period by either party

G 070 WATERCOURSESAny person desiring to do work in a natural

watercourse or channel where no City easementexists must file an Application/Permit (Form 3.651)with the City. When approved, this form becomes anatural watercourse permit (non-revocable). Theengineer must review the description of the workproposed to be done, investigate the site, anddetermine whether the work meets Cityrequirements.

Before the City requirements can bedetermined, the engineer must first determinewhether the work constitutes a part of the City’spermanently improved drainage system. If so, an“A” or “B” permit is required and the City stormdrain and permit requirements (including thededication of a drainage easement and/or Waiver ofDamages to the City) must be met by the applicant.If not, the work is a private improvement (ownedand maintained by the property owner) subject tothe requirements of watercourse regulations(Sections 64.07 to 64.10 of the Municipal Code).The permit requirements are given in the Operationsand Control Manual.

There are no set rules by which the futurealignment of a permanent City storm drain can bepredicted. Therefore, the engineer’s good judgmentin his evaluation of existing conditions must berelied upon to determine City requirements. .Romefactors which favor the construction of a

permanent City storm drain under a “B” permit are asfollows:

1. The construction of a storm drain conduitwhich is aligned between two improved portions ofor extends from an existing City storm drain.

2. A major improvement of a watercoursewhich receive runoff from streets or other publicproperty.

3. The choice of an applicant to construct apermanent storm drain under City inspection forpossible future acceptance by the City.

Some factors which favor the construction of aprivate storm drain under a watercourse permit are asfollows:

1. The construction of drainage facilities in anisolated or unimproved area.

2. The improvement of a watercourse whichdrains private property only.

3. Minor repairs, alterations, inlet structures,etc.

The type and extent of work allowed under awatercourse permit must meet the following criteria:

1. The work must not obstruct or interfere withthe flow of water in the watercourse, and

2. The work must not injure adjoiningproperty. (See Liabilities, Section G 012.) A11conditions and restrictions of construction should bestipulated on the permit.


G 080June, 1969

G 080 DRAINAGE COMPLAINTS

Throughout the year, and particularly duringinclement weather drainage complaints are receivedby the City from property owners. In general, theCity is not liable for damages caused by floodconditions. However, in the public interest, the Citywill investigate the complaints to determine whetherany relief can be given. The Engineering Districts,or Divisions of jurisdiction shall be responsible forhandling drainage complaints in their respectiveareas.

The procedure for handling drainagecomplaints is as follows:

1. The complaint shall be taken (by telephoneor at the public counter) without comment orsurmises as to the action to be taken by the City. Asimple statement that the complaint will beinvestigated as soon as possible is sufficient. Theform Drainage Complaint Report (Figure G 080)shall be filled in except for the Investigationportion, and the complaint shall be immediatelyreferred to the responsible engineer.

2. The responsible engineer shall grantdrainage complaints top work priority and endeavorto investigate the complaints while flood conditionsexist, or as soon as possible thereafter. A thoroughinspection of the site shall be made to determine thecause of flooding (or damage), and arecommendation to relieve the situation (ifpractical) is made. If no immediate action can betaken, the ultimate solution is recommended forfuture action. The investigation report should not bedisclosed to the public prior to approval by thesupervisor. Also, particular care shall be exercisedto avoid any statements or implications from

which possible liability of the City for any flooddamage might be inferred.

3. As soon as the investigation is complete, theinvestigating engineer must acquire approval on therecommendation by the District/Division Engineer(or his representative) before any action can beundertaken. A change in recommendation by theDistrict/Division Engineer shall be made on thecomplaint form. The contemplated action can thenbe taken, and the complaint form is given to themapping section for posting.

4. The draftsman shall post the complaint incarmine ink at its location on the drainage map. Theletters “DC” and the year and month of the complaint(681) are the only information posted. The complaintform is then filed chronologically in the DrainageComplaint file.

The City Attorney recommends against givingadvice as to rights of adjoining property owners inprivate drainage matters. The property owners shouldbe informed that the matter is private and should besettled by the property owners involved in thedispute. If the property owners can agree on a mutualsolution of their drainage difficulties, it would beproper to assist them with engineering advice as tosizes of pipes, grades, etc.

No inspection will be made, nor will anyinspection undertaken proceed, in the presence of anylegal representatives of the complainant or attorneysunless the City Attorney is also represented. Anyarrangements for inspections with legalrepresentatives must be made by the City Attorney’soffice.

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