chapter 5 on-farm soil & water conservation

8/18/2019 CHAPTER 5 On-Farm Soil & Water Conservation.

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CHAPTER 5: ON-FARM SOIL & WATER CONSERVATION1:

1. INTRODUCTION: It is essential to understand that there is a need for conserving the soilin order to ensure continuos productivity. It is only by efficient use and management of soil that

its productiveness can be maintained over an extended period of time.

1.1 The use and management of soil includes:1.1.1 Planning, in order to determine proper use.

1.1.2 Preparation of soil for planting.

1.1.3 Treatment of soil for the production of plants.

1.1. !omplete plant nutrition and care.1.1." Proper harvest and post#harvest practices.

$ater is a precious, natural, rene%able resource and the basis for all life. It must be treated %ith

care and long term planning in order to ensure, as much as humanly possible, that it is, andremains, available to nurture all living things.

1.2 The &istrict of 'bbottabad is very much in need of (oil ) $ater !onservation *easures

for the farm, such as:

1.2.1 !onservation Planning.1.2.2 +and esources Inventory.

1.2.3 !rop otation.

1.2. !ontour -arming.1.2." (trip#!ropping.

1.2. Terracing.

1.2./ -arm &rainage.1.2.0 ully !ontrol.

1.2. 'uifer echarging.

1.2.14 $ater 5arvesting.1.2.11 rass $ater%ays.

1.2.12 $atershed *anagement.1.2.13 !onservation Irrigation.If a realistic and pragmatic vie% is ta6en of our present circumstances %e are bound to come to

rather disappointing conclusions. The good ne%s is that there is tremendous scope of

improvement and enhanced productivity. 7ur negligent and harmful practices are under#utili8ing

%hat could be bountiful and abundant productivity. The severity of the present problems has been reduced largely due to the overnments reen evolution of the 14s. The time has no%

come to initiate a rass oots, reen evolution. This can only be done through realistic

planning and concentrated implementation. The use of locally produced modern, 5i#Tech, yetlo% cost materials can substantially reduce the negative impact of many of our problems. There

is absolutely no point in being Technology (hy9 Plant utrition, as detailed previously, through

the use of 21st

!entury utrition products is one such step. 'nother step, that can and should beintroduced, is the use of 'nionic Polymers or Polyacrylamides, for reducing soil loss through

erosion. (oil losses have been reduced to as little as 2.3 megagrams per hectare, as compared to

141 megagrams per hectare on treated and control plots respectively2. The effects of Polymer

1 *ost of the material in this chapter has been derived from the !ourse material of a &iploma

;*aster !onservation< of the orth 'merican (chool of !onservation, (cranton, P', =.(.'.2 +aboratory of >iomedical and ?nvironmental (ciences, =niversity of !alifornia, +os 'ngeles,

10. $allace and $allace.

!reated by (irdar Timur 5yat#@han 130


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!oncentrations on -urro% Irrigation have sho%n that over a range of application rates, of at least

4./ @gsA hectare and mean of 1.3 @gsA hectare, there %as a furro% sediment loss reduction by

B and increase in net infiltration by 1" B3. Cet another step, that has achieved ama8ing results inthe =nited (tates in the 134s, %as the formation of !onservation &istricts. $e can easily

duplicate this success by underta6ing similar efforts. $hile the proposed methodology is detailed

else%here, some important steps that can be underta6en follo%.

2. CONSERVATION PLANNING: The basic %ealth of any !ountry is its atural esources.

These are divided into rene%able and non#rene%able. ' Dust and euitable use of these resourcesis a rational use that provides benefits to all and ensures that this use is sustainable. This means

using %ithout using up. ?nsuring that atures abundance is not abused and only used in such a

manner that it continues to provide its living abundance to all coming generations. $e are

presently concerned %ith t%o of the three maDor rene%able resources. These are the soil and%ater. 7ur present and past usage of these resources leaves much to be desired. The ?cological

(ystems that sustain us are inter#lin6ed and fragile. Thoughtless over exploitation renders them

subDect to degradation and eventual failure. (ome of the immediate threats %e are facing, in

'bbottabad &istrict, due to our negligence are:2.1 (oil erosion.

2.2 &ecline in soil fertility.2.3 Increased soil borne pests.

2. &enuded $atersheds.

2." avaging flash floods.2. Increasing aridity.

2./ eceding $ater Tables.

2.0 !limate change.

This results in reduced agricultural capacity, %hile population pressures continue to mount. Toovercome these grave problems it is all the more necessary to ma6e detailed and realistic plans

for proper soil and %ater use and their conseuent reDuvenation. (ubseuently it is imperative

that these plans be carried out in letter and spirit. The first conclusion that is dra%n from any preliminary survey of the &istricts +and and $ater usage is that it is inappropriate to say the

least. Primary data, that has been collected, supports this statement. In order to come up %ith a

realistic !onservation or (ustainable &evelopment 'ction Plan the first step is to ma6e a +andand $ater esources Inventory. This is subdivided into +and and $ater.

3. LAND INVENTORY: It is important to 6eep in mind the reason of ma6ing a +and

Inventory. This is to provide the reuisite Primary data that %ill enable maximum and rationaluse of every acre of land %ithin the &istrict. *aximum in terms of economic returns that 6eeps

in mind limited resources. ational in terms of harmony %ith ature and sustainability for

coming generations. ' +and Inventory is the first step to%ards ascertaining +and capability. Thisamounts to mapping the land to sho%:

3.1 @ind of soil %ith respect to:

3.1.1 (oil !haracteristics:EaF ?ffective soil depth.

EbF Texture of topsoil.

EcF (oil permeability.

3 +ent8 and (oD6a. =( &ept. of 'griculture, Idaho, 1.



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EdF Type of parent material.

3.1.2 +and !haracteristics:

EaF (lope.EbF &egree of erosion.

EcF $etness of soil.

3.2 ?ffective (oil &epth.&epth of a soil, do%n to a restrictive layer such as bedroc6 or hard pan, is 6no%n as ?ffective

(oil depth. This is the depth to %hich plants roots can penetrate and moisture can be stored:

Table 1: ?ffective (oil &epths:

(r ange &escriptive Term (ymbol

1 G 4 inches. Hery deep 1

2 3 # 4 inches. &eep 2

3 24 # 3 inches. *oderately deep 3

14 # 24 inches. (hallo%

" 4 # 14 inches. Hery shallo% "

(oil depth is determined %ith the help of a soil auger.

3.3 Texture of topsoil: The surface to 0 inches of soil is called the topsoil. This is the depththat is normally %or6ed in soil tillage operations. (oil texture is a good indicator of soil

erodability and rate of infiltration of %ater into the soil. The relative proportions of the various

si8e groups of individual soil grains in a mass of soil are the benchmar6 of soil texture. (ilt, clayand sand %ith less than 2#mm diameter are considered. The amount of these three materials in a

representative soil sample determines its texture class. The higher the percentage of sand the

lighter the soil and as silt and clay content increases, the soil becomes progressively heavier.

Table 2: Topsoil Texture:

(r Textural !lass &escriptive Term (ymbol1 5eavy clay. Hery fine Every heavyF H

2 !lay, silty clay, sandy clay, silty dry loam, clay loam. -ine EheavyF 5

3 !lay#loam, silt#loam, loam, very fine sandy loam. *edium *

-ine sandy loam, sandy loam, loamy fine sand. !oarse Every lightF +

" +oamy sand, sand, coarse sand. Hery coarse Every lightF !

$ell decomposed organic soil. *uc6 7

/ =ndecomposed organic soil. Peat P

0 Texture classes not separated. =ndifferentiated

The occurrence of coarse fragments in a soil, in sufficient uantities to influence land use,

sometimes necessitates further modification of textural classes. These are represented by lo%er#

case letters, %hich precede the above upper#case symbols.

Table 3: Topsoil Texture *odifiers.

(r (i8e ange &escriptive Term (ymbol

1 -ragments up to 3 inches in diameter. ravelly g

2 -ragments 3 to 14 inches in diameter. !obbly c

3 -ragments more than 14 inches in diameter. (tony s

oc6 outcrops of the bedroc6. oc6y r



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3. (oil Permeability: This is defined as the ability of air and %ater to move through a soil.

Infiltration rate is the rate at %hich %ater enters a soil from the surface. 's opposed to this soil

permeability is measured as the amount of %ater that %ill pass through a column of saturatedsoil, of a given cross#section, under a specific hydraulic gradient, in a unit of time. The number

that represents soil permeability is related to the rate of %ater movement through that soil under

the top 14 inches. This number gives the soil permeability up to a point %here a different 8one of permeability exists. This 8one is not to be confused %ith the 8one that restricts root penetration

and is restricted to the effective soil depth. Therefore in case such a 8one exists in the soil under

examination, t%o numbers are given representing the t%o permeability 8ones. In cases of deepsurveys, for example those reuired for drainage systems, a third number is given. In such cases

the first number %ill represent permeability at a depth of 14 to 3 inches, the second at a depth of

3 to " feet and the third %ill represent permeability from " to feet.

Table : (oil Permeability:

(r ate inches per hour Probable texture !lass (ymbol

1 J than 4.4" Hery fine or fine Hery slo% 1

2 4.4" to 4.2 Hery fine or fine (lo% 23 4.2 to 4.0 -ine or medium *oderately slo% 3

4.0 to 2." *edium *oderate

" 2." to ".4 !oarse *oderately rapid "

".4 to 14.4 Hery coarse apid

/ G than 14.4 Hery coarse and gravelly Hery rapid /

3." Parent *aterial: Primary soils are those that have been formed by soil forming processes

from the underlying material. In the case of primary soils, the underlying parent material is

al%ays sho%n, regardless of depth. (econdary soil is that soil that has been formed from soilmaterial that has been transported from some other location by %ind or %ater.

Table ": =nderlying *aterial:

(r *aterial (ymbol

1 'cid crystalline roc6 '

2 >asic crystalline roc6 >

3 (erpentine !

+oess &

" (hale, fine#grained sedimentary roc6 ?

(andstone, coarse#grained sedimentary roc6 -

/ lacial material

0 +imestone +

*uc6 *14 Peat P

11 (and K

12 !emented hardpan L including hard caliche

13 (emi#consolidated alluvium (

1 +acustrine material H

1" !laypan C



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1 ravel M

3. (lope: (oil and $ater !onservation is influenced to a large extent by the degree of slope of

the land. (lope is represented in percentage and this has been grouped according to influence onerosion and %ater. ' one# percent slope means one foot vertical drop for 144 feet hori8ontal

distance. Table : (lope of +and:

(r (lope ange in Percent &escriptive Term (ymbol

1 4 to 2 early level '

2 2 to " ently sloping >

3 " to *oderately sloping !

to 1 (trongly sloping &

" 1 to 31 *oderately steep ?

31 to "1 (teep -

/ "1 to / Hery steep

0 / plus 5

(lope of land is usually measured %ith a hand level. (lopes are not al%ays uniform and as such

do not al%ays fall into the ranges given. In such case it is possible to combine t%o or moresymbols, e.g. !& or a slope that ranges from " to 1 percent. In cases %here slopes are uniform

the symbol can be preceded by the exact percentage, e.g. 0!.

3./ (oil ?rosion: (oil erosion refers to removal of soil by natural forces such as %ater or %ind.The degree of erosion is classified by studying the soil profile and by degree of gullying that has

occurred.

Table /: &egree of ?rosion:

(r ange &escriptive Term (ymbol1 J 2" B of original topsoil or original plo%ed layer

removed.

o apparent, or

slight, erosion

1

2 2" to /" B of original topsoil or original plo%ed layer

removedN occasional gullies may be present.

*oderate erosion 2

3 -rom /" B of original topsoil to 2" B of subsoil

removedN occasional deep gully or freuent shallo%

gullies may be present.

(evere erosion 3

'll original topsoil and 2" to /" B of subsoil removed. Hery severe erosion

" Intricate net%or6 of very freuent gullies. Hery severe gullies "

3.0 &egree of $etness: &egree of %etness is the amount of free %ater %ithin the normal root8one. $here it interferes %ith normal plant gro%th, it is ta6en into consideration. $ater in the

root 8one may be the result of slo% drainage or due to a fluctuating %ater table. This should not

be confused %ith soil permeability, as a soil %ith good permeability may be %et due to poor underlying drainage.



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Table 0: &egree of $etness:


1 !hoice of crops slightly limited, or planting dates slightly

delayed

(lightly %et land $1

2 !rops are moderately affected or planting dates delayed *oderately %et land $2

3 !rops seriously affected or delayed Hery %et land $3

(%amp or marshN too %et for cultivated crops ?xtremely %et land $

(ome land is subDect to overflo% at varied intervals and for varied periods of duration.

-reuency of this action and length of duration may affect farming operations. In such cases it is

included in the +and Inventory.

Table : -reuency of 7verflo%:


1 !rops occasionally damaged or plantingdelayed

7ccasional overflo% or of shortduration

f1

2 !rops freuently damaged or range of crops

limited

-reuent overflo% or of long

duration

f2

3 ro%ing of cultivated crops not feasible Hery freuent overflo% or of

very long duration

f3

3. (tandard mapping (ymbols: The symbols sho%n above are standard, in order to overcomeany possibility of confusion. -urther they are represented on the map, in a standard manner, as a

fraction symbol. (oil characteristics are sho%n as the numerator and land characteristics as the

denominator.

(oil:

(lope # ?rosion

-rom a +and Inventory it is possible to determine the ability of the land to produce and the typeof action that must be ta6en to protect it or enhance its productivity.



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-igure 1: (tandard *apping (ymbols.

4. LAND CLASSES: +and classes are divided into t%o main categories:

.1 (uitable for !ultivation.

.2 ot (uitable for !ultivation.These are further divided into sub#categories:

.1.1 !lass I: &eep, nearly level land that is not easily erodable. (uitable for all types of

crops as determined by limiting factors li6e climate and light intensity..1.2 !lass II: ood land %ith moderate limitations. 'ny one of the factors that are

determined by the +and Inventory and less than ideal, cause this distinction.

.1.3 !lass III: *oderately good land that can be cultivated %ith regular crop rotation.

.1. !lass IH: This is land %here long rotation bet%een pasture and grain crops should be maintained on a 3 L year basis.

.2.1 !lass H: These may be level and not subDect to erosion but may be unsuited to cultivation

due to limiting factors as determined by the +and Inventory..2.2 !lass HI: These may be some%hat limited to pasture or forest because of shallo% soils or

steep slopes.

.2.3 !lass HII: These have severe limitations for pasture or forestry..2. !lass HIII: These lands are not suited for cultivation, pasture or forestry.

-igure 2: +and !lasses.



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5. CROP ROTATION: The gro%ing of different crops in succession on the same land is calledcrop rotation.

".1 The benefits of crop rotation are:".1.1 educing soil erosion: o% crops %hich are placed 2 to 0 inches apart reuire freuent

cultivation and leave little or no crop residue. The exposed soil bet%een ro%s is subDect

to erosion. +ess distance bet%een ro%s and more crop residue left behind, decreases soilerosion. $hen different types of crops are gro%n on a piece of land in succession the

overall result is lesser erosion.

".1.2 Improving yields: &ifferent types of crops ma6e different demands upon the soil or

fertili8ers reuired. They also leave behind different types of residue. -or example aleguminous crop %ill leave behind a surplus of fixed itrogen. The soil %ill benefit from

these demands and supplies made by various plants. $hen this factor is used

intelligently, i.e. fertili8ation and rotation by carefully selected or recommended crops,

the soil %ill benefit and productivity %ill be enhanced.".1.3 &isease, insect and %eed control: &ifferent types of crops are host to various 6inds of

pests and are subDect to different types of diseases. $here monoculture is practiced these pests and diseases get the opportunity of finding a constant host. $here rotation is

practiced this is obviated and pestOs life cycles are interrupted. &ifferent types of

cultivation and %eeding reuirements also interrupt the seeding of %eeds.".2 There are many factors involved in the choice of a cropping system for a particular piece of

land. !ropping systems should be flexible and permit change of acreage of crops from year to

year. 7bviously, financial considerations are additional to physical limitations.

".3 The planning of a cropping system reuires three uestions to be borne in mind:".3.1 $hat properties of the soil, in a field, reuire particular attention, in order to ensure

efficient production, %hile maintaining or enhancing soil productivity in the long term

".3.2 $hat different methods can be used to control crucial soil factors".3.3 $hat crops %ill fetch the highest returns and yet allo% attention to the above uestions

6. CONTOUR FARMING: The practice of plo%ing and planting across, rather than up anddo%n, the slope is termed as !ontour -arming. The obDective of such an exercise is to conserve

soil and %ater. In arid areas this practice results in slo%ing do%n runoff and allo%ing it to soa6

into the soil. In humid 8ones this results in preventing soil loss. This practice results in better

yields. This is due to the fact that increased moisture content in the soil, even in humid 8ones, provides moisture to the plants during lean or drought periods.

.1 @ey !ontours: In order to be able to plo% along the contour the farmer needs one, or

more, 6ey contour lines on each field. The purpose of a 6ey contour is to guide the farmer in the plo%ing operation. In the case of short slopes, one 6ey contour line half%ay do%n the slope is

sufficient. In the case of long or irregular slopes, several 6ey contour lines may be needed. Thelaying out of 6ey contour lines is a relatively simple operation. 'll that is reuired is a hand level

and a fe% sta6es. The first step is to determine %hich portion of the helpers body Eshoulder, chin

or hairlineF is the sighters eye level, %hen both are standing on level ground. $hen sighting

through the level, if the hairline is against this portion of the helperQs body, both are standing atthe same elevation. The next step is to choose a 6ey contour. ' sta6e is driven into the ground

!reated by (irdar Timur 5yat#@han 1"


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and the level is set up. The helper moves along this contour in as much a level course as

possible. $hen he has traveled the predetermined distance, the sighter loo6s through the level.

5e signals any adDustment in the helpers position that may be reuired. $hen the sighter issatisfied he signals the helper and the next sta6e is driven into the ground. The sighter then

moves to the position of the ne% sta6e and the process is repeated until the line is completely

established. In case the contour line crosses a %ater%ay, it should stop and not disturb anyvegetation. 7nce all sta6es are driven the line can be established by plo%ing.

.2 !ontour Tillage: This is one of the simplest practices to conserve %ater and soil. It is

most effective on slopes from 2 to 0 B and reduces soil and %ater loss from 24 to 4 B. This practice is also effective in improving angelands. $here grasses have deteriorated to short,

soddy gro%th it has been found that contour tillage %ith furro%s to inches across and not

more than " feet apart, improve the vegetative gro%th. If higher grasslands undergo contour

tillage the effect on neighboring lo% land is reduction of silting from 0" to " B.

-igure 3: !ontour Tillage.

/. STRIP-CROPPING: If sloping land is left bare during the rainy season, it is subDect

to erosion. (uch land is best protected by strip cropping. ' farmer can plant his crops in

large bloc6s or complete strips. 7n the other hand it is advisable to divide the fields intonarro% strips. This is done in order to protect clean#tilled strips of corn %ith non#

cultivated strips of small grain or hay. +arge sloping fields that are plo%ed and cultivated

at the same time are subDect to the maximum amount of erosion during the period %henno crop has yet gro%n. ' viable alternate is to plo% and cultivate alternate strips. This



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ensures that erosion#resistant crops are gro%ing bet%een clean#tilled areas. It is then

possible to practice crop rotation and use all standard soil conservation practices in order

to ensure minimum erosion.

/.1 (trip#!ropping Hs !ontour Tillage. (trip#cropping is a vegetative form of soil erosion

control as opposed to the mechanical method of !ontour plo%ing. The t%o methods are roughlysimilar in %ater conservation but strip#cropping is by far better in soil conservation. The

effectiveness of strip#cropping depends upon the plants that are gro%n in the strip. (odded

grasses are the best soil conservation plants. 5o%ever, there is no financial return offered. Thelegumes and hay crops are the best financial alternate. +egumes hold the added advantage of

fixing itrogen and hay crops provide fodder for !attle.

/.2 Types of (trip#!ropping:

/.2.1 !ontour (trip#!ropping: This type is a combination of (trip#!ropping and !ontour Plo%ing. !rops are planted in strips, placed cross%ise to the slope and follo%ing the

contour. &ense erosion#control crops alternate %ith clean#tilled erosion permitting crops.

/.2.2 -ield (trip#!ropping: In undulating slopes, %ith no true contour, the method of field

strip#cropping is used. 5ere the crops are planted in strips, in roughly uniform parallelro%s, laid cross%ise to the general slope.

/.2.3 $ind (trip#!ropping: 5ere crops are planted in strips, cross%ise to the prevailing %ind,%ithout regard to the contour of the land. This method is recommended on level to nearly

level land, %here soil erosion and %ater conservation are not a problem but %ind erosion

is the factor that needs attention./.2. >uffer (trip#!ropping: ' sod crop, made up of grass or legumes, or a mixture of both,

%hen planted bet%een strips, in regular rotation, is called buffer strip#cropping. These

buffer strips are usually laid on those portions of a slope that are badly eroded and not

suitable to regular cultivation./.3 *anaging (trip#!ropped -ields: !areful planning and installation of strip#cropping %ill

enable permanently maintained fields. It is necessary to alternate the method of plo%ing in order

to avoid build up of high ridges over the years. Turning the land up the slope is also desirable, inorder to allo% seeping of %ater under the furro% slice. This is done by using a t%o %ay turning

plo% to turn all the furro%s in one direction. In case strips are irregular in %idth and both sides

are approximately on the contour, planting should be done from both edges in%ards to the center of the strip. This enables the placing of the greatest number of long ro%s on the contour and the

short ro%s in the center. egular rotation, except on strips most prone to erosion, should be

carried out. It should be 6ept in mind that the denser the vegetation and the longer the crop stays

on ground the less the danger of erosion. Plants %ith extensive root systems, li6e small grains,are better placed to protect the soil. Perennial legumes have dense vegetation and a fibrous root

system that results in a dense sod. This provides the most protection. In humid areas %here ro%

crops are alternated %ith small grains, the former are planted up slope of the latter. This is done because the ro% crops reuire deeper furro%s and higher ridges. This provides some protection

against erosion. The small grains do not have this advantage and the soil is subDect to erosion

until they emerge./. !omputing (trip 'creage: In order to determine the yield per acre it is necessary to 6no%

the amount of acreage that is planted for a particular crop. This is relatively simple in large bloc6

fields. In the case of strips, the follo%ing chart is used for computing acreage. This is done by

6no%ing both the average %idth and length of the strip. +ocate each point on the t%o sides of the

!reated by (irdar Timur 5yat#@han 1/


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chart and dra% an imaginary line bet%een them. The point %here this line intersects the central

acreage line, is the acreage of the strip.

-igure : !omputing (trip 'creage.

/." 'dvantages of (trip#!ropping: This practice has been demonstrated to be a very economicalsystem and a practical means of preventing, or reducing, erosion and %ater loss on cultivated

land. There are many advantages in (trip#cropping and this practice is highly recommended for

'bbottabad &istrict. (ome of these advantages are:/.".1 educed length of slope do%n %hich %ater runs retards the momentum of %ater.

/.".2 (lo%er momentum increases infiltration and shedding of soil particles.

/.".3 &ense vegetation gro%ing in alternating strips further retards %ater momentum.



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/.". (oil is opened by root systems and earth %orms. &ense vegetation on the sod strips

prevent silting of these pores.

/."." (trip#!ropping results in a large number of small fields, %hich in turn encourage croprotations.

/.". Installation of strips is not expensive.

/."./ *aintenance of strips is lo%./.".0 &egree of accuracy, as reuired for terraces, is not as high. *ista6es can be rectified on

the next plo%ing.

/.". Time and energy are conserved as long strips are easily plo%ed, %ith fe%er turnsinvolved.

/.".14 +ess po%er is used %hen plo%ing across a slope rather than up and do%n.

/.".11 educed runoff results in reduced loss of plant nutrients, resulting in turn, in higher

yields./. *easuring the (lope: ' fe% simple tools can give us an accurate estimate of the slope of a

land. These are a yardstic6, a straight piece of stic6 exactly "4 inches long and a carpenters level.

The method is as follo%s:

/..1 +ay the stic6 on the slope./..2 aise the lo%er end until the stic6 is level as sho%n by the carpenters level.

/..3 *easure the vertical distance from the do%nhill end of the stic6 to the surface of theground.

/.. This reading, in inches, %hen multiplied by t%o gives the percent slope.

In the case of regular slopes a single reading is sufficient. In the case of irregular slopes it%ill be necessary to obtain several readings and compute the average.

-igure ": *easuring the (lope.

0. TERRACING: The basic function of a terrace is the interception of %ater. This %ater is

either slo%ly absorbed in the field or slo%ly conducted from the field. In areas %ith less

than 34 inches of rainfall the terrace is built to allo% interception into the soil rather thanrun off the surface. ' graded terrace %ill intercept the flo% of %ater before it can reach a

velocity that is high enough to damage the land. In level terraces, %ater is held until it



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can soa6 into the ground. (andy, stony or very shallo% soils are not suited for terracing.

They are expensive to construct and difficult to maintain.

0.1 -actors that &etermine (uitability of (oil:

0.1.1 Permeability and erodibility of a soil %ill vary and %ill influence the cross#sectional

dimensions, grade and spacing from one terrace to another.0.1.2 (oil (tructure: This is important for determining the season of the year in %hich the

terrace should be constructed, the ease %ith %hich it is constructed, and the time, po%er

and type of euipment needed for construction. -or example, if soil that is high in claycontent, cloddy to massive in structure and is %or6ed %hile %et, it %ill compact under

heavy euipment and destroy permeability.

0.1.3 Texture: >onding levels bet%een individual particles of soils, determine suitability of that

soil for terracing. -or example sandy soil terraces %ill not last long.0.1. &epthA 5ardpan: In shallo% soils or %here a hardpan exists Eunderlying clay 8oneF, %ater

is absorbed only to a limited amount. This results in excess runoff and destruction of the

terrace.0.2 ?conomics: Terracing correctly is an expensive proposition. In order to be cost effective,

some situations may %arrant crop rotations, strip#cropping or contour tillage. These methods of

erosion control and %ater conservation are much less expensive and may be the only measuresthat are either reuired or suited to the situation. In high rainfall areas %ith long slopes it may be

economically necessary to install terraces.

0.3 Types of Terraces: Terraces may be classed as:

0.3.1 'bsorption Type.In lo% rainfall areas %ater conservation is of primary importance. ' ridge is the best

structure for increasing absorption over a %ide area above the ridge.

0.3.2 Interception or &iversion Type.If %ater is in plentiful supply, then interception or diversion is desirable. 5ere %ater is

intercepted in the terrace and diverted do%n a gentle gradient. Thus velocity of %ater

flo% is reduced. This in turn reduces erodibility. ' channel that is some%hat belo% theoriginal ground surface is best suited to intercepting and diverting runoff %ater.

0. 'reas %ith moderate rainfall and favorable soil conditions may need a combination of

both types. Terraces may also be classified according to method of construction:

0..1 The >road !hannel Terrace conducts excess rain%ater from fields at non#erosivevelocities. This consists of a %ide and relatively shallo% channel of lo% gradient %ith

gentle side slopes and ample %ater capacity. ?xcavated earth is used to heighten the

lo%er side of the channel and to add %ater capacity. The ridge should blend %ith thesurface slope in order not to interfere %ith euipment. The do%nside of the ridge should

also conform to the slope to reduce danger of erosion.

0..2 ' idge Terrace controls erosion indirectly by conserving %ater and permitting it to soa6

into the ground. The terrace is so constructed as to ensure maximum spread of %ater andavoid concentration in small ponds. 'bsorption rates and rainfall patterns are carefully

studied %hile designing such terraces. This type of terrace is adapted to area %ith lo%rainfall.

!reated by (irdar Timur 5yat#@han 1"4


14/52

0..3 >ench Terraces are one of the oldest mechanical methods of erosion control. These

transform land %ith 1" to "4 B slopes into a series of level steps running across the

slope. (ince topsoil is moved from the upper portion of the terrace, artificial fertili8ation,incorporation of organic matter and green manuring are used to regenerate the soils

fertility. This type of terrace is in use in 'bbottabad &istrict, li6e most of the

mountainous orth. 5o%ever, %ater conservation or diversion is not practiced.

-igure : Types of Terraces.

0." !ultural Practices on Terraces:

=se of euipment is an important factor %hile designing terraces. !losely spaced or steep slopes

%ill not allo% the use of euipment. !ropping practices are also a factor for design. !ertaincrops protect soils from erosion. The degree to %hich a crop protects soil during adverse seasons

and the stage of gro%th during seasons of intense rainfall is of particular importance. Proper

management and maintenance of the terrace %ill determine success. -aulty tillage can lead to



15/52

ruin. It is desirable to till the land on the contour. To plant crops in ro%s that are parallel to the

terrace. Thereby creating small ridges that aid in slo%ing do%n the flo% of %ater. Terracing can

be combined %ith strip cropping to control erosion and %ater movement. !ertain features of these t%o control systems must be 6ept in mind %hile combining them, these are:

0.".1 *a6e strips as uniform as possible in order to practice crop rotation.

0.".2 ?nsure that at least one ro% of a strip falls bet%een adDacent terraces, ridge or broadchannel. This ensures that a portion of each terrace interval is protected by close gro%ing

crops.

0.".3 ?liminate areas %here ro%s come to a point, as far as possible, by including irregular areas in the strip.

0.". =se as fe% strips as possible in order to provide effective erosion control.

-igure /: Planting >et%een Terraces.

-igure 0: 7perating *achinery on the !ontour.



16/52

-igure : Planting on the Terrace, *ethod '.



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-igure 14: Planting on the Terrace, *ethod >.



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0. Terrace !onstruction: It is important to include all erosion control factors in a terrace

design. &rainage %ater%ays, slope changes, roads, boundaries, and large gullies must be

considered.0..1 5ydraulics: 5ydraulics ta6es into consideration the action of the movement of %ater.

ainfall and conseuent movement do%n the slope is ta6en into account. Terraces are

designed to slo% do%n this flo%. ?xcessive rainfall and subseuent rapid flo%s %illerode the soil, especially in the case of plo%ed land. 't velocities of 2 or more feet per

second, %ater %ill loosen and move soil from unprotected land. 's %ater moves do%nhill

it gathers velocity. Terraces intercept run#off before velocities reach harmful rates. (lopeof the land, velocity of run#off and amount of rainfall are thus the first factors ta6en into

account %hile designing terraces.

0..2 Helocities in Terrace !hannel: ' terrace channel, an essential part of the terrace and most

often missing in our terraces, must be capable of containing maximum expected run#off.Its %idth should be broad enough to carry %ater at non#erosive velocities. -lo% of %ater,

in a terrace channel, increases as slope increases, as depth of %ater increases and as

roughness of a channel decreases. >road, flat channels allo% greater volumes of %ater to

flo% %ithout increasing velocity. It is important to maintain a uniform cross section alongthe channel. In order to be able to handle increasing volumes of %ater, gradients are

increased along successive portions of the channel. The upper portions of the terraceshould contain flatter grades in order to retard the flo% of %ater. This is necessary in

order to disallo% %ater from piling up in the lo%er reaches of the terrace.

0..3 *anning the Terrace (ystem: (ites for outlet or disposal channels have to be selected before a terrace can be constructed. >road, natural %ater%ays %ith natural vegetation are

the most preferable feature. 7utlets are usually planned and constructed several seasons

before a terrace is constructed. This allo%s plenty of time for their stabili8ation. The best

outlet channel is a %ide flat or parabolic structure. radients should be B or less. !areshould be ta6en in selecting vegetation cover in the outlet. &ense and deeply rooted

grasses can stand velocities up to " to / feet per second.

0./ +ocation: The location of a terrace must cater for:0./.1 !ontrol of surface %ater.

0./.2 7peration of farm euipment.

0./.3 euirement of minimum maintenance.0.0 Terrace (pecifications: -actors to be considered %hile developing terrace specifications:

0.0.1 (lope.

0.0.2 ainfall.

0.0.3 un#off ates.0.0. (oil !haracteristics.

0.0." Tillage 7perations.

0.0. Hegetative !over.0.0./ !ultivation Practices.

0. enerali8ations:

0..1 +imiting +and (lopes: (lopes greater than 12 B usually limit the possibility of building aterrace.

0..2 (pacing: The spacing of terraces varies inversely %ith the steepness of the slope. This

means that as a slope becomes steeper, the distance bet%een terraces decreases. ' basic

spacing formula can be used:

!reated by (irdar Timur 5yat#@han 1""


19/52

HI R (A3 S 2

HI R Hertical Interval.

( R (lope in percent.

Hertical interval is the vertical distance from the bottom of one terrace to the bottom

of the terrace immediately belo%.

0..3 rades: (teep grades result in high velocities of run#off. Hariable grade control is better than uniform grade. The maximum advisable grade is inches per 144 feet of length.

0.. +ength of Terrace. The maximum length of a terrace that carries %ater in one direction is

1,44 feet. (horter terraces are more desirable for controlling run#off.

0.." Terrace $idth: This depends upon the follo%ing considerations:EaF Terrace must have ample channel capacity to handle %ater flo%ing into it.

EbF !hannel and ridge side slopes must be able to permit the use of farm machinery

%ithout brea6ing do%n the sides of the terrace.

EcF *ust be economically practical.0.14 Terrace !onstruction.

0.14.1 +ocate all ridges and depressions0.14.2 rade the intended terrace to drain from the ridge to the natural drainage %ay if possible.

0.14.3 (ta6e the upper terrace, using the drainage divide as a starting point from %hich to

measure the vertical interval.0.14. ?ach succeeding terrace is sta6ed in turn. The outlet end of a terrace is a convenient point

to start sta6ing. (ta6es are normally "4 feet apart on the centerline of the terrace ridge.

$hen the terrace goes over a ridge or through a depression, sta6es are normally set 2"

feet apart.0.14." 'fter sta6es are set, it may be necessary to realign them to eliminate sharp curves and

ma6e for easier construction and eventual cultivation.

0.11 Terraces can be constructed by any type of euipment that %ill move soil and can gainaccess to the area. Terraces reuire attention and maintenance every year to 6eep them in their

original condition. It must be borne in mind that there is an intimate and complex relationship

bet%een all (oil !onservation measures li6e !ontour -arming, (trip#!ropping, rass%ater%ays, =se of fertili8ers and Terraces.



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-igure 11: =sing a >ulldo8er to >uild Terraces.

!reated by (irdar Timur 5yat#@han 1"/


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-igure 12: =sing a Tractor to >uild Terraces.



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. GULLY CONTROL: In areas of heavy rainfall and steep slopes, gullying is a serious

problem. $here natural vegetation has been allo%ed to flourish, the cover provided to the soil

allo%s the force of raindrops to be decreased. un#off is also slo%ed do%nN this results in %ater being allo%ed to sin6 into the ground instead of accelerating erosion. This charges the auifers

and maintains topsoil cover. (oil ta6es millions of years to build. It can be %ashed a%ay in a

matter of days. Topsoil is a precious asset and determines the fertility of the land. aturallycharged auifers are another great asset and our very survival depends upon them. Thus it is

important to maintain vegetative cover and also to plug any gullies that have been created.

ullies are usually formed in the natural %ater%ays and drainage lines of the physical relief. It is possible to stabili8e gullies or improve them to act as reservoirs or %ater disposal systems.

ullies are considered by si8e, a small gully is 0 feet or less in depth. *edium gullies are from 0

to 1" feet deep and large gullies are those above 1" feet in depth. &rainage area is considered as

that area %hich provides the run#off that enters the gully. ullies %ith less than "4 acres drainagearea are considered as small drainage areas. &rainage from "4 to 1"4 acres is considered as

medium and drainage areas above 1"4 acres are considered as large drainage areas. 7bviously

the most cost#effective gullies to control are small gullies %ith small drainage areas.

.1 Improvement *easures: These consist of:

.1.1 -encing: +ivestoc6, that is allo%ed to gra8e openly, have a detrimental effect uponemerging gullies. -encing readily protects small gullies %ith small drainage areas. +and

that is badly gullied and cannot be restored to cropland is usually treated in this manner.

-ences should enclose the area completely and be set bac6 enough to allo% natural re#vegetation to ta6e root and protect the gullies from further deterioration. In case natural

re#vegetation is too slo%, or difficult to establish, planting a mixture of grasses, shrubs

and trees can help the process.

.1.1 atural Hegetation: egular erosive flo% of %ater often %ashes a%ay seed and young plants. ' good mulch of stra%, t%igs or leaves %ill control this action. The steepness of

the sides of the gully %ill also determine the degree of natural re#vegetation. The steeper

the slope the more difficult is it for plants to be established. (lopes of 1 to 1 grades areabout the limit for natural vegetation to ta6e root. $or6ing the slopes can help this along.

.1.3 'rtificial e#vegetation: This depends upon the eventual use to %hich the gullied land is

to be put to. In case a natural drainage %ay is desired, grass is the best cover and providesmore erosion control than %oody plants. Thus hay can be made from the area. In case

drainage is not so important the area can be planted %ith a desired species of trees for

-arm -orestry. rass plantations can be made by any of the follo%ing methods:

EaF (eeding. This is only possible %ith fertile soil and seed bed preparation.EbF (olid (odding. (od strips of usually 1 foot %idth and 0 to 14 feet length are cut

and placed as continuos cover. (od can be stapled do%n or covered %ith %ire

mesh to allo% it to establish before facing heavy run#off.EcF >roadcast (odding. 'n inexpensive alternate, that saves time and labor, is to dis6

up existing sod and dis6 into the bed of the gully. This method can only be used

%ith grasses that propagate themselves through the roots. The fertile soil androots can establish themselves in the gully. This method ta6es longer for the gully

to be stabili8ed.

EdF (trip and (pot (odding. 5ere trenches are made in the same dimensions as the

strips that are to be transplanted. This method is used along %ith seeding in the



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intervals bet%een strips. (pot sodding is the transplanting of small clumps of

grass, %ith intervals, over the area to be planted.

EeF (od !hec6s. This method stabili8es gully channels until natural re#vegetationta6es hold. The (od (trip is suited to small gullies %ith small to medium drainage

areas. (od (trips are laid across the gully channel either flush %ith or slightly

belo% grade. (trips should be a minimum of 12 inches %ide and should run up atleast inches above the expected %ater line on each side of the gully. The spacing

of the strips depends upon the spreading nature of the sod, the drainage area and

the grade of the gully. (pacings of " to / feet are common. !ontour (od (trips areused %here gully sides are steep and it is difficult for natural vegetation to

establish.

-igure 13: (od#(trip ully (tabili8ation.

EfF Trees and (hrubs: In case it is desirable to replant the gully %ith trees and shrubs,only those species should be selected that are usually gro%ing in the area. This is

due to the fact that they are acclimati8ed and better suited to adapt to harsh

gro%ing conditions of gullies. (olid planting of one species is best avoided.&isease incidence and insect attac6 can lead to failure of the entire stand. (everal

species have the advantage of less competition and can also contribute to disease

control by lac6 of similar environment to particular types of pests. *ixed

plantations also encourage %ildlife. (pacing of plants depends upon species of planting and condition of the gully. 5o%ever, feet either %ay is best suited for

erosion control. (hrubs can be planted at 3 and feet either %ay. Planting is

avoided on steep slopes or steps cut into the slope. It is also advised that planting



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on overhangs and too close to edges should be avoided. (mall or medium si8e

gullies can also be stabili8ed by the use of shrubs and sta6es. 5ere shrubs are

planted across the flo% of the gully channel at to " inch intervals and are protected by sta6es. (ta6es are placed 1 foot do%n the channel from the shrubs in

order to ma6e use of accumulated silt for the shrubs. (hrub chec6s reduce

velocities of flo% and induce silting. They can only be used in gullies %ith mildgrades.

.2 (tructures: (tructures are used %here protection has to be provided and vegetation cannotdo the Dob adeuately. These structures are either temporary or permanent. In case run#off is

limited, the structures can be temporary until natural vegetation can ta6e root. Temporary

structures can consist of brush, poles, %ire and loose roc6s. In the case of heavy run#offs,

permanent structures are used. These should be made of durable material li6e masonry, concrete,metal or earth. $here ever possible, it is advisable to supplement structures by vegetation.

.2.1 Temporary (tructures: These are used to collect and hold soil at the bottom of the

gully till vegetation is established. They can also be used to chec6 erosion in thegully head or in the channel of the gully. In cases of negligible run#off, compacted

stones or brush on the bottom of the channel is usually sufficient. (everal lo%chec6 dams are more effective than one large structure. 'n average height of 1

foot is usually the limit. 7nce these chec6 dams silt up, vegetation can protect lo%

over#falls more easily than high ones. (pacing can be regular or siting at critical points to protect vegetation can be used. The latter method results in fe%er dams

and less costA effort. This type of structure is used in gullies %ith small drainage

areas. (oil collected is less in uantity but is sufficient to allo% the establishment

of vegetation. The structures should be constructed far enough into the bottom of the gully to prevent %ashouts underneath or around the edges of the dam.

(ufficient capacity, to channel a%ay run#off, should be included. 'n apron, that

prevents the undermining action of run#off, should also be provided.

EaF >rush &ams: This type of dam is used %here soil conditions permit the driving of

anchoring sta6es. The type of brush available, the si8e of the gully and its physical condition %ill determine the type of brush dam that is to be constructed.

It is important to remember that the center of the dam should be lo%er than its

sides in order to allo% the %ater to flo% over rather than to%ards the sides of the

dam.



25/52


26/52

is used the >utt ends are pulled through the %ire mesh to be held by the fill. The

apron should be at least feet long and extend 2 feet on each side of the posts that

form the level portion of the spill%ay. ' tie pole anchored %ith sta6es can be usedto compress the brush. The apron should be counter sun6 and shorter brush should

be used near the upper end, to produce a shingle effect. ' layer of fine mulch can

be laid under the brush to provide a better bonding %ith the surface. It is desirableto promote rapid filling and sealing of the structure. To obtain this, stra%, fine

brush or similar material is pac6ed against the %ire on the upstream side to the

height of the spill%ay. This is then bac6ed %ith %ell#tamped earth of at least 2 to1 slope. The spill%ay crest can be sodded to prevent channeling along the lip. The

minimum value of ;d< in the illustration belo% should be 10 inches.

-igure 1": $oven $ire &am.

EcF +oose oc6 &ams. These are desirable in accordance to availability and ease of transportation. ullies %ith moderate slopes and small to medium drainage areas

are best suited for this type of structure. If flat stones are used they can be 6eyed

together to provide for a very durable structure. In case rounded or irregular

stones are used it is advisable to hold them in a %oven %ire net. ' trench to the



27/52

depth of 1 foot is made across the gully at the proposed site. This is the base for

setting the stones. The roc6s are laid in ro%s across the gully and overlapped to

produce the shingle effect. 7nce again the center of the dam is 6ept lo%er than thesides. (everal large and flat stones are counter sun6 belo% the spill%ay to serve as

the apron. They should extend to about 3 feet do%nstream of the base of the dam.

-igure 1: +oose oc6 &am.

EdF Plan6 or (lab dams. This type of dam can be used in gullies %ith larger drainage area

than those %here %oven#%ire or brush dams can be used. This type of dam is

constructed %ith plan6s of %ood or %ith slabs of concrete. The latter is preferable, to conserve on %ood and ensure durability. If the material can be

readily transported this type of dam is uic6est in construction. Pre formed !!

slabs can be readily used to construct the dam in a matter of hours. This dam alsouses the conventional aprons and trench base.



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.2.2 Permanent (tructures: These are built %here permanent %ater%ays are intended. 'lso

large gullies %ith large drainage areas can support the construction of such structures. If

%ater is to be stored on a permanent basis, this is the type of structure that is reuired.There also exists the possibility of generating 5ydel Po%er from these *ini dams. -ish

can be readily stoc6ed and the %ater can also be used for irrigation and drin6ing supply

purposes. In all cases it is more advisable and economically feasible to build multi# purpose mini dams %here ever possible.

-igure 1/: Permanent (tructure ?arth -ill &am.



29/52

The preceding illustrations are that of one 6ind of a -arm Pond that %ill suit many uses. >y far

the most important aspect, in this type of pond, is the spill%ay. If the spill%ay is too small there

is every li6elihood of failure of the pond. ' combination of Pipe and (ide spill%ay is the best.The Pipe spill%ay is for normal flo% %hile the side spill%ay is for emergencies. 7nly extra run#

off goes into the side spill%ay. Therefore it is possible to 6eep it in good sod cover, as it is dry

most of the time. The bottom of the side spill%ay must be higher than the top of the pipespill%ay. The distance, in height, bet%een the t%o is sho%n, as ;(< in illustration >. This

distance %ill vary in accordance to the si8e of the %atershed and that of the pond. It is possible to

arrive at the right value of ;(< by dividing the si8e of the %atershed, in acres, %ith the si8e of thesurface of the pond, also in acres. The result is then divided by . -or example a %atershed of ."

acres divided by a pond surface of 4.2" acres %ill yield 10 to be divided by . Thus a figure of 3

feet as the value of ;(< or distance, in height, bet%een the bottom of the side spill%ay and the

top of the pipe spill%ay is established. This value of 3 feet is also the limit in height differential.In case this value is higher than 3 feet a different type of spill%ay %ill have to be designed by an

experienced engineer. +ong experience has determined the si8e of a spill%ay. >y allo%ing the

proper distance ;(< bet%een the pipe and side spill%ay the follo%ing si8es for spill%ays %ill

suffice.

Table 14: (pill%ay (i8e.

$atershed 'rea

In acres.

&iameter of Pipe (pill%ay

in inches.

>ottom %idth of (ide

(pill%ay in feet

" acres inches " to 0 feet

14 acres inches 0 to 14 feet

14 to 24 acres 0 inches 14 to 1" feet

24 to 34 acres 14 inches 1" to 24 feet

The bottom %idth of the side spill%ay is increased by 1 foot for each 2#acre increase in

%atershed area greater than 14 acres..3 $eed !ontrol: $eed gro%th in ponds can be stopped by some simple measures..3.1 ?liminating shallo% edges.

.3.2 -ertili8ing the pond to ensure a ;>loom< of algae. This results in cutting off light as the

%ater is clouded and %eeds cannot start gro%ing. It also provides fish %ith their primary

source of food.-igure 10: !ontrolling $eeds.



30/52

14. FARM DRAINAGE: The central ash Plain in the 'bbottabad valley is poorly drained.

In %et years this leads to extensive damage to crops and a reduction in yields. The

drainage of %et croplands, that are fertile, is one of the most important of conservationfarming measures. Production on these lands can be greatly increased %ith proper

drainage. $ith drainage, more ro% crops can be gro%n on flat lands. This reduces the

pressure on steep sloping land, %hich then can be used for close gro%ing crops. -armdrainage must be carefully planned and implemented in order to ensure the desired

results. $et soils are cold due to the fact that it ta6es more heat to %arm %ater rather than

soil. &rained soils have their moisture content replaced %ith air. To gro% %ell plantsreuire %armth and air in their root 8ones. -riendly bacteria are also facilitated. &rained

soils can be %or6ed earlier in spring and seeds germinate faster. Plants also do not dro%n

after rains. !rops that are planted on %et lands are often subDect to burn out. In %ater

saturated soils, plant roots spread on the surface in spring and early summer. +ater,during summer drought the %ater table falls belo% the root 8one and the crop is starved

of %ater. oot penetration is deeper in %ell#drained soils and plants are thus drought

resistant.

-igure 1: &rainage ?ffect on Plants oots.

14.1 Types of &rains:

?xcess %ater can be drained by either:aF 7pen (urface &rains.

bF Tile &rains.

7pen surface drains occupy land and interfere %ith farm euipment. They readily cho6eup %ith %eeds and reuire constant maintenance. =nless they are deep, they %ill drain

only the surface and not the soil. Tight soils in humid areas ho%ever, reuire these types

of drains. Tile drains neither %aste land nor interfere %ith farm operations. They need

little care %hen installed and drain the pores of the soil. Thus roots spread %ithout



31/52

interference. $ith !eramic 'dobe !onstruction it is possible to manufacture tile drain

material in abundance and at very little cost as a by#product1. 'deuate drainage systems

involve a number of farms or even a %hole area. ' land capability map as a basis for farm conservation %ill provide the necessary information for planning a drainage system.

(uccessful farm drainage also includes plans for controlling erosion on the land, in

ditches, on spoil ban6s and outlets. They include plans for farming the drained land incrop rotations that bring about good soil tilth or structure. Plans for 6eeping the drains

%or6ing properly are also incorporated. The installation of a proper outlet for drainage

%ater is of prime importance. ormally %ater is discharged by gravity into a natural%atercourse. !ommunity enterprises for such schemes are the beast course for planning,

implementation and maintenance. In surface drainage, %ater is removed through open

ditches. These field ditches open into larger collection ditches until they reach a natural

or artificial %atercourse. -ield ditches should be laid out parallel and spaced "4 to 1"4feet apart. 's reuired by the soil, surface conditions and the crops to be gro%n. The area

that is to be drained %ill depend upon the rate of flo% of the %ater into the ditch, its si8e,

its grade Eslope or rate of fall of %ater surfaceF and its irregularity. This irregularity is

effected by the roughness of the ditch section, debris and vegetation gro%ing in the ditch.The amount and timing of rainfall, the slope of the land and the condition of the soil and

plant cover, determine ho% uic6ly %ater runs into the drain. 7n level or gently slopingland, field and outlet ditches, to drain up to 44 acres, should be large enough to remove

at least 2 inches of %ater from the area in 2 hours. Tables 11 and 12 sho% the areas that

small H shaped and flat#bottomed ditches %ill drain, in grades up to 4." feet per 144 feet. Tables 11 ) 12: !omputing &rainage 'reas.

1 ?xtremely pertinent to PunDab, (indh and %here ever $ater+ogging is a problem.



32/52

-lo%ing %ater %ill erode the soil. In many cases it is desirable to enforce lo% %ater velocity by

constructing the ditch is sections having less fall than the natural slope and connecting these

sections %ith drop spill %ays. &rop spill%ays are recommended %herever the average velocity of the flo% %ill exceed feet per second in clay loams.

The tile drain is the best type of under drain. $ater moves into the drain through gravity flo% by

entering through the Doints bet%een the tiles. +ay of the land and location of the outletdetermines the placing of drains. In rolling land, these drains can be laid by lines of tiles in the

natural %atercourses. ?xtra branch lines are laid, as needed, in %ide %et areas. This type of

arrangement is called a andom (ystem.

-igure 24: andom (ystem.

If the land is too %et, the !omplete (ystem is a better option. The main drains follo% the natural%atercourses of surface flo%. +aterals are laid in parallel lines, or groups of parallel lines, under

the %hole area. +aterals should be straight and run in the general direction of the greatest slope.

They should be laid at such intervals and at such depths, as the land reuires.

'n impervious layer of soil, that stops the do%n%ard flo% of %ater, usually causes %et areas atthe bottom of valleys. This situation can be corrected by laying tile drains or combining them

%ith 'uifer echarging $ells. 5ere the tile drainOs outlet leads to the inlet of the recharging

%ell. Thus %e achieve the added advantage of draining the soil as %ell as recharging of theauifers. This combination is particularly suited to the ash Plain.



33/52

!reated by (irdar Timur 5yat#@han 1/4


34/52

-igure 21: !omplete (ystem.

The drains should be laid deep enough to intercept %ater flo%ing along the top of the impervious

layer. These drains should be spaced so as to lo%er the ground %ater enough for good plantgro%th %ithin 2 hours after a rain.



35/52

-igure 22: Intercepting &rain.

The ground %ater surface is a curve that is lo%est at the drains and ordinarily highest mid%ay

bet%een them as sho%n in the follo%ing illustration.

-igure 23: round %ater +evel.



36/52

14.2 !onstruction: The soils structure and texture affect the rapidity %ith %hich drains lo%er

the %ater. !lay soils, %ith a tendency to crac6, greatly help the drains as %ater flo%s more

readily through the crac6s. In tight clay soils, %ater movement is very slo% and drains must be placed closer to the surface and closer together. In clay and clay loams, as in the ash Plain,

drains should be placed 4 to /4 feet apart and 2." to 3 feet deep. o drain should be less than

2." feet deep. In other %ords, the bottom of the drain should be 2." feet belo% the surface. +argedrains should be placed deeper. The drain should have a minimum of 2 feet soil cover. This is

necessary in order to avoid brea6age due to the passage of machinery. In silt loams, drains can be

placed 4 to 144 feet apart and at depths of 3 to feet. 'll tile drains should be deep enough to be free from frost damage.

(i8es of tiles, for mains and sub#mains, depend on many factors. -irstly, %here surface drains

carry off a large part of the %ater after storms, tile drains have to cater for only that part that

seeps into the ground. ' four#inch tile is the smallest that can be used in tile drains. ' five#inchtile carries nearly t%ice as much %ater and is less susceptible to bloc6age by sediment. There are

t%o methods of establishing grade for tile drains. These are age and +ine and Target method as

outlined belo%:

-igure 2: age ) +ine *ethod.



37/52

-igure 2": Target *ethod.

14.2.1 unctions bet%een laterals and main tile drains should be made %ith COs, not TOs or elbo%s. !hanges in direction are made by curves and not by sharp angles. !urves should be 6ept

regular %ith the outer side of the Doints covered %ith pieces of bro6en tile.

-igure 2: &irection !hanges.

14.2.2 (ome circumstances %arrant the use of relief %ells. This occurs %hen tile drains flatten

out and the tile in the flatter part is not large enough to ta6e care of the resulting pressure %hen

there is a heavy flo% into the system. These %ells are best located at field borders so as not to

interfere %ith mechanical %or6. The illustration belo% depicts a relief %ell.



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-igure 2/: Pressure elief.

11. AUIFER RECHARGING: The !ity of 'bbottabad %as rescued from a %ater crisis,in summer of 2444, by the advent of timely rains. The famous springs at Ilyasi *asDid had dried

up and a number of the tub%ells, bored in the recent past for *unicipal $ater (upply, %ere also

in the same process. otices to commercial users had begun to be issued to ma6e their o%narrangements for %ater. This extremely alarming situation %as averted in the nic6 of time.

5o%ever, it is pertinent to point out that this incident should serve as a timely notice and

immediate measures be underta6en to ensure that such a dangerous situation does not ariseagain. The reasons of this near failure of the %ater supply are varied. *any have been covered in

previous and succeeding sections. 5o%ever, the most important and immediate cause is lac6 of

auifer recharge at a rate commensurate %ith %ithdra%al. *uch Public *oney has beenexpended in the boring of deep %ells %ithin the valley of 'bbottabad. The auifer that is already

sorely depleted has sun6 even further. -irstly, it is necessary to ma6e alternate arrangements for

*unicipal $ater (upply. (econdly, auifer recharging can be done by the sin6ing of dry bores

and allo%ing accumulated surface %ater to penetrate into and thus recharge the auifer. This pioneering activity %ill serve as an example for the rest of the !ountry, %hich is facing similar

problems in and around large urban areas. It is extremely important to note that a great deal of

care must be exercised to ensure that no pollution is carried do%n into the auifer. The preceding

section on -arm &rainage can prove to be a starting point for such an exercise.11.1 ash Plain &rainageA echarging !omplex. The area of the ash Plain that is effected by

poor drainage can serve as a catchment area for recharging. -irstly, it %ill be necessary tomotivate the o%nersA %or6ers of the land to organi8e themselves into a regular !ommunity

>ased 7rgani8ation. $ith organi8ation, the members can ensure that harmful chemicals and

se%erage does not enter into the drainage scheme that is outlined in section 14. 7nce this is

ensured, they can construct their drainage scheme %ith the help of the best technical expertiseavailable. Instead of allo%ing runoff to drain a%ay, it can be impounded and allo%ed to settle

into the auifer. This %ill readily recharge it in the light of heavy rainfall experienced in the area.

This subDect needs to be examined and studied %ith great care.

12. WATER HARVESTING: *ining of underground %ater resources at the rate of maf and recharging at a rate of 2 maf, leaves a deficit of / maf annually %ith fluctuations from year to year.1 Per capita reuirements of 1/44 cubic meters is the cut off point for rene%able %ater

supplies. The present irrigated agriculture has 34 B efficiency in %ater use, %hereas drip and

sprin6ler irrigation has a " B efficiency factor. This also increases yields from 24 to 4 B. Inorder to use any 6ind of irrigation it is essential to firstly have %ater. The increasing aridity of

the past fe% years has amply proved the dire necessity of initiating concentrated efforts to%ards

1 Innovative irrigated agriculture, &r. Mafar 'ltaf, -ederal (ecretary *I-'+, 2444.

!reated by (irdar Timur 5yat#@han 1/"


39/52

the harvesting of %ater. $ater harvesting, in this context, means the collection of runoff for

productive purposes. The mountainous &istrict of 'bbottabad is home to %hat is the beginning

of the $ater To%ers represented by the (i%ali6s and the mighty 5imalayas. These %atersheds provide the collection point to the large underground auifers that %e have long ta6en for

granted. The problem of recharging auifers is dealt %ith separately. 't present %e are concerned

%ith the collection of excess rainfall, in periods of plenty, to be utili8ed in an efficient manner inlean periods. (mall land holdings mean that such activities can be carried out at lesser cost and

yet prove to be cost effective. euisite %ater, provided at critical periods, can ma6e intensive

agriculture and horticulture very beneficial to those %ho underta6e the reuired effort.

12.1 ain $ater !atchment =tili8ation E$!=F: This is the third alternate to surface and

ground%ater resources. It has some advantages over the first t%o and these are:1

12.1.1 $!= %ater costs as little as 1Ath to 1A0th that of long distance truc6 hauled %ater.12.1.2 Investment in $!= can be repaid in #" years Ecan be further brought by the use of

!eramic 'dobe Technology2F.

12.1.3 &ecrease in runoff, due to harvesting, %ill be only 4.1 to 4." B of total river flo%.

12.1. ain%ater is less polluted than surface or ground%ater.12.1." ain%ater is usually %idely distributed and closer to home than surface or deep ground

%ater.12.1. $!= systems are relatively simple and can be constructed by the end users %ith little

external assistance.

12.2 *icro $ater !onservancy $or6s3 have proved to be extremely successful and beneficialin !hina. Hast proDects have been underta6en in installing large and small %ater cisterns.

This activity %as carried out in hilly areas %here other types of %ater %or6s %ere not

feasible. The proDect has brought %ater to the homes and fields of countless, long#

suffering peasants. These lo% cost and uic6 return proDects, are the ans%er to drought problems for hillside farming.

12.3 Types of +ocal $ater 5arvesting (ystems: These include:

12.3.1 od @ohi Type:$ater cascading do%n from the hills is stored in a series of successive earthen dams and

directed to%ards the fields as and %hen reuired. This is only possible, %ithout conflict,

in cases %here the local community is organi8ed and %ater rights are pre#determined. Inthe (ulaiman *ountains of >aluchistan such a system has long been in practice. $ater is

only allo%ed to flo% through the main channel and is diverted to side channels %hen it is

excessive. The local farmers have found three %ays of saving the fast flo%ing hill

torrents. These are:aF Pond (ystems: !onstruction of = shaped di6es in the path of the torrent. The

%ater is allo%ed to spill out of the di6e in various directions.

bF $ild -lood (ystem: $ater is diverted, from natural courses, to%ards smallimpoundment.

1 ain%ater 5arvesting, (aleem '. (ial, I!I*7&, 2444.2 @hidmat -oundation, ?(!'P( !onstruction Technology, 10.3 *icro#$ater !onservancy $or6s, ?xamples from &eyang !ity, !hina, 5e Cufang, 1. Indigenous to Pa6istanOs (ulaiman anges, >aluchistan.



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cF +evel &i6e (ystem: +ong and level di6es are constructed. $ater is allo%ed to

flo% in a 8ig 8ag manner across the slopes through the entire system. This allo%s

recharge of the auifers.1

(ome of the preceding >rush and $ire type &ams can also be utili8ed. In any case, the

local system is functioning adeuately and 1,44 cooperatives exist to maintain, utili8e

and regulate it12.3.2 ooftop 5arvesting: The construction of large E2,444#+iter capacityF -erro#!ement Dars

and placement at the spout that channels rain%ater from rooftops has proved to be a

relatively inexpensive and proficient system. *ore than one Dar can be lin6ed in tandemas per reuirementsA rainfall. It is suggested that !eramic 'dobe !onstruction can replace

this type of material. $hen combined %ith homesA stores construction, the Dars can be a

viable by#product.

12.3.3 Traditional (pring $ater 5arvesting: The development of small springs and their roofingA protection is a long established practice in the $-P. ?xcess %ater can be channeled to

irrigate fields.

12.3. !oncrete +ined (urfaces: This relatively expensive alternate is used to construct tan6s or

cisterns. unoff is directed to%ards these tan6s. $hen combined %ith a roof, evaporationis reduced. The efficiency of such a system in high.

12.3." Plastic +ined (urfaces: This type of lining is much less expensive and cost effective. The pond is lined %ith blac6 plastic. The plastic can be covered %ith mud in case animals

E%ater buffaloesF use the %ater and trample the lining. This type of harvesting is efficient,

uic6 to establish and can be roofed %ith branches and t%igs to provide an inexpensivealternative to the pucca tan6sA cisterns.

12.3. !ompacted (oilA ley (urfaces: 'n even more inexpensive alternate is to line the bottom

of a tan6 %ith fresh manure and cover %ith pegged in banana leaves. The fibrous material

decays to bloc6 up the soils pores and a relatively efficient %ater retention capacity isestablished. (uch types of tan6s have the added advantage of holding fish as the material

provides nutrition to microscopic algae that is their food.

12.3./ oads and Paved (urfaces: ?xisting roads and paved surfaces can benefit greatly by theconstruction of storm drains. These drains can lead to%ards storage systems and provide

a source of harvesting the runoff.

12.3.0 !ontour +ine &itching: (mall holding tan6s are constructed along natural drainage%ater%ays or courses. This can also be done along the contour line for feeding %ater to

lo%er fields, as and %hen reuired. These holding tan6s can be of any of the above

materials or types.

12. (torage (ub#systems: These are of the follo%ing types:12..1 $ater cellar.

12..2 $ater tan6.

12..3 $ater DarA cistern Eabove and underground or roofedF.12.. PondsA reservoirs.

12." $ater =se ?fficiencyN In order to ensure success of the harvesting scheme it is necessary

to use harvested %ater in a %ise and appropriate manner. (ome of this is covered in a later section.

1 $ater 5arvesting for *ountain 5ouseholds in Pa6istan, &r. Mafar 'ltaf, federal (ecretary

*I-'+, 1.

!reated by (irdar Timur 5yat#@han 1//


41/52

13. GRASS WATERWAYS: ' natural or man#made %ater%ay, protected %ith a sod cover,

is %hat is meant by grass %ater%ays. atural %ater%ays are usually the best alternate. In case

these are of insufficient capacities to meet runoff reuirements. 7r if they interfere %ithcultivation, man#made %ater%ays can be established and seeded %ith a good sod grass. The

dense vegetation and fibrous roots of the sod grass are the best cover to protect a soil from

erosion. *ost of the Terraces and cultivated slopes in the &istrict do not ma6e use of thisarrangement. This results in massive soil erosion and conseuent loss of valuable and fertile

topsoil. It %ill be of great benefit to channel %ater from terraces or from ro%s of cultivated fields

into existing natural %ater%ays. -or this purpose artificial %ater%ays %ill have to be developed.

13.1 (i8e: The expected heaviest runoff, in a ten year period, %ill be the maDor determining

factor in si8ing a %ater channel. $idth and depth must cater for this flo%, to ensure success and

the protection of such a measure. +arge %ater%ays that are designed to service large areas canalso be used as pastures. In such a case it is advisable to 6eep the %ater%ay on the larger side in

order for it to cater to this dual usage.

13.2 (hape: ' dish or parabolic shape is ideal for a %ater%ay. This design spreads the %ater and avoids great depth %hile maintaining large capacity. It is also easy to construct. The H

shaped %ater%ay %ill %or6 %ell if the top %idth is 12 times the depth. This type can be modified

to have a flat bottom resulting in a trape8oidal cross#section. The nature of %ater flo%s cause parabolic shaped natural %ater%ays. (imilarly trape8oidal or H shaped %ater%ays %ill also

develop a parabolic shape %ith the passage of years.

-igure 20: (hape of the &itch.

13.3 (uccessful ?stablishment ) *aintenance of $ater%ays:

13.3.1 $ater%ays should be located in natural drainage paths, %hereever possible.13.3.2 ?xcess vegetation that might interfere %ith the flo% of %ater should be cleared a%ay.

13.3.3 In case of seeding a sod grass the seedbed should be prepared in a firm manner.

*ulching, to protect soil and seedlings, should be carried out.13.3. (od grass that is best environmentally suited or native to the area should be used.

13.3." Planting should be carried out at the appropriate time.

13.3. In case fertili8ation is reuired Eusually on introduced grassesF it should be done in

accordance to the needs of the soil and grass variety.13.3./ 7ver seed to ensure a thic6 stand and repair bald spots %ith sod.

13.3.0 'void using the %ater%ay as a road, especially %hen the surface is %et.

13.3. =se the %ater%ay moderately for gra8ing and hay. 'llo% re#establishment before%inter. 'void gra8ingA mo%ing %hen grass is %et.

13.3.14 Inspect %ater%ays after heavy rains and repair immediately %hen reuired.

13. $atersheds: $ater%ays are an integral part of %atersheds. The land surface from %hich%ater drains and is channeled into %ater%ays, streams and rivers is called a %atershed. ' small



42/52

%atershed protection program should be initiated and implemented in the &istrict. Together these

small %atersheds form large %atersheds or the drainage systems of the &istrict. This program

should include:13..1 -orestation and eforestation.

13..2 $ater%ay improvement.

13..3 epair of ullies.13.. !onstruction of flood prevention chec6 dams.

-igure 2: $atersheds.



43/52

1. CONSERVATION IRRIGATION: !onservation Irrigation means, using irrigated soils

and irrigation %ater in a manner that results in high levels of production, %ithout %asting either soil or %ater. This involves the combined use of cropping, irrigation and cultural practices that

enable a farmer to use his land permanently and also maintain high levels of productivity.

1.1 In other %ords, !onservation Irrigation results in:

1.1.1 (aving %ater.

1.1.2 !ontrolling soil erosion.1.1.3 Increasing crop yields.

1.1. +o%ering production costs.

1.1." >ringing more land under irrigation as less %ater is reuired.

1.2 !onventional Irrigation: -lood irrigation is the conventional irrigation system that is being practiced %here %ater is available. !ontinuos gro%ing of ro% crops, %ithout replacing

organic content of the soil, results in brea6ing do%n of soil structure. The ability of %ater to

enter and flo% through the soil and provide moisture to the plants is severely restricted. $ater is

forced to run off and this results in erosion and loss. (econdly, uneven leveling of the fieldsresults in over irrigation of the upper end of a field in order to ensure that the lo%er end receives

enough %ater. 7ver irrigation restricts oxygen inta6e by a plantQs root. This results in damagerather than benefit. The delivery of %ater in open ditches is another source of %ater loss by

seepage and evaporation. This loss ranges from 2" to /4 B depending upon the nature of the

soil, amount of %ater, climate and velocity of %ater flo%. $eeds gro%ing in %ater channels slo%do%n the flo% of the %ater and also use %ater for their o%n gro%th. $ater is also lost, before it

is used for irrigation, due to uncontrolled logging and gra8ing in the %atersheds. This results in a

change in the flo% patterns of streams and rivers as %ell as reduced recharging of auifers. '

change in flo% patterns means flooding in spring and during the monsoon period and reducedflo%s during the rest of the year. 'dditionally, reservoirs and irrigation channels and canals are

subDect to siltation. This reduces their capacity to hold or carry %ater. This leads to the added

cost of removing the silt or %asted reservoirs.1.3 (olutions: ' thorough %or6ing 6no%ledge of the soil, topography, %ater reuirements of

various plants and the capability of the land to be irrigated is reuired in order to be able to use

the basic principles of soil and %ater conservation. *aximum control is exercised over %ater from delivery to application. $ater should %et the root 8one, %ithout losses, through deep

percolation or runoff.

1. 7n#-arm !onservation Irrigation: This entails the use of irrigation and cropping methods

that are best suited to the slope of the land, crop that is being gro%n and the amount of %ater supply available. The follo%ing steps need to be ta6en.

1..1 (oil ) $ater esources Inventory: The land inventory, as discussed earlier, in the shape

of a soil conservation survey map is a pre#reuisite to good planning. (econdly %e must6no% the amounts, timing and duration of %ater supply and the possibilities of improving

this supply.

1..2 *ethod of 'pplication: $ater may be applied to crops in a number of methods. It isnecessary to 6eep in mind available resources and possible alternatives:

a. eticulation: (ub#soil irrigation through perforated pipes buried in the root 8one.

This method can be made viable and inexpensive through the use of permanent no#till

beds and second hand pipes. It is the most efficient form of irrigation and can be



44/52

controlled through the use of inexpensive tensiometers to regulate %ater supply. This

type of irrigation is suited to expensive ro% crops.

b. &rip Irrigation: This is the supply of %ater to individual plants either through buriedor surface emitters. The '! has helped to develop inexpensive supplies for this type

of irrigation. (econdly, inexpensive alternates such as used glucose drip bags can be

used. This type of irrigation is suited to -ruit production and can be automated throughthe use of tensiometers.

c. >ubbler Irrigation: This is a type of drip system %ith a modified emitter that

enables adaptation of the system to enable use in ro% crops. The emitter is above groundand more uantities of %ater are emitted.

d. *oving and (tationery E(olid (etF (prin6ler (ystems. The '! has developed

locally manufactured and inexpensive ain uns. These rain guns provide a circular

%etting 8one of fine sprin6led %ater. $ater supply varies from 1 to 2 inches and %etting8one from 144 to 1"4 feet diameter. The rain gun can be used as a static sprin6ler or

mounted upon a moving trolley E244 feet lateral move, 144 feet %etting 8oneF. !ircular

and lateral movements are affected by hydraulic pressure. The only reuirement is for

piping and pressure pumps. &egree of rotation can be set through simple mechanicalstops. The trolley system is best adapted to permanent beds %ith standby reticulation to

ma6e a hybrid system. This system provides the most efficient irrigation that can deliver liuid based fertili8ers Esafe and stabili8edF in precise uantities as and %hen reuired.

This is 6no%n as -ertigation. 7bviously the system should only be employed for high

value horticulture crops. (tand#alone sprin6lers are suited to cereal crop production.5o%ever cost of installation renders them cost effective for hybrid mai8e producing 44

to "44 @gs per 6anal.

The exact amounts of %ater reuired depend upon soil and types of crops irrigated. 5o%ever, a

rule of thumb developed through practical application sho%s that %ater reuired for 1 6anal of flood irrigation can irrigate 14 6anals if applied through sprin6ler and up to "4 6anals if applied

through drip and reticulation systems. Thus %here 1 6anal flood irrigation %ater %as available

"4 6anals of high production horticulture can be maintained. This represents a substantialincrease in income and generation of economy. It is %ell %orth the costs and efforts reuired.

1..3 Planning the &istribution (ystem. The distribution system must ensure that %ater reaches

all parts of the farm. It should be ensured that a minimum amount of land is used and that%aste%ater can be disposed.

1.. +and Preparation: *aximum efficiency of irrigation entails careful land preparation.

+eveling of land must be as precise as possible.

1." !onservation -lood Irrigation: $here it is not possible to employ special conservationirrigation systems, conservation flood irrigation can be used. (ome of the methods are:

1.".1 >asin Irrigation: The target field is di6ed and uic6ly filled %ith %ater to the desired

depth. $ater is allo%ed to soa

chapter 5 on-farm soil & water conservation

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