Building Services :Drainage, Rain Water Disposal and Harvesting

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Drainage- Sub- drains, Culverts, Ditches, Gutters, Drop inlets and Catch Basins,Rain Water Disposal for individual buildings, Rain Water Harvesting with examples and illustration for 4th ,P.T.U



2. sr834 CONTENTS- Drainage- Sub- drains, Culverts, Ditches, Gutters, Drop inlets and Catch Basins. Rain Water Disposal for individual buildings. Rain Water Harvesting 2 3. sr834 STORM DRAINAGE SYSTEMS A storm drain is defined as that portion of the storm drainage system that receives runoff from inlets and conveys the runoff to some point where it is then discharged into a channel, water body, or piped system. It consists of one or more pipes connecting one or more inlets. A storm drain may be a closed-conduit, open-conduit, or some combination of the two. The terminology "storm sewer" which has been in general use for many years, is gradually being replaced with the term "storm drain" to differentiate between sanitary sewers and storm drains. Storm drain will be used throughout this manual. 3 4. sr834 THE PURPOSE OF A STORM DRAIN IS TO COLLECT STORM WATER RUNOFF FROM THE ROADWAY AND CONVEY IT TO AN OUTFALL. STORM DRAIN DESIGN GENERALLY CONSISTS OF THREE MAJOR PARTS: system planning which includes that gathering and outfall location; pavement drainage which includes pavement geometries and inlet spacing; location and sizing of the mains and manholes. 4 5. sr834 REQUIREMENT FOR THE STORM WATER DRAINAGE Stormdrain systems should have adequate capacity so that they can accommodate runoff that enters the system for the design frequency.z Storm drain systems should be designed with future development in mind if it is appropriate. The storm drain system for a major vertical sag point that can't overflow elsewhere until the depth of water is two feet or greater, should have a greater level of flood protection to decrease the depth of ponding on the roadway and bridges. Where feasible, storm drains shall be designed to avoid existing utilities. The recommended minimum distance is 10 feet when the storm drain system is parallel to the waterline and 1foot when the storm drain system crosses a waterline. Attention shall be given to the storm drain outfall design to insure that the potential for erosion is minimized. Drainage system design should be coordinated with the proposed staging of large construction projects in order to maintain an outlet throughout the construction project period. The placement and hydraulic capacities of storm drainage structures and conveyances should be designed to take into considerationpotential damage to adjacent property and to minimizetraffic interruptionby flooding as is consistent withthe importance of the road, the design traffic service requirements, and available funds. Storm drain placement and capacity should be consistent with local storm water management plans. 5 6. sr834 SUBDRAIN A subdrain system is an underground network of piping used to remove water from areas that collect or retain surface water or groundwater. The network can be rather small, such as might be used to drain a limited area, or fairly large to drain a sizeable number of acres. Surface water can be collected into the subdrain system by installing a surface inlet or catch basin. Groundwater is collected by allowing water into the pipe through perforations. Both surface water and groundwater can be discharged to an appropriate outlet such as a nearby storm sewer, pond, or river. Both storm drains and subdrains are installed underground to carry water away from homes and businesses. Storm drain pipes are connected to the aboveground storm drain grates and primarily carry surface water runoff through the system. Subdrain pipes are not directly connected to the storm drain grates. instead, subdrain piping contains holes that allow the intake and passage of groundwater through the underground system. Subdrain piping has been installed in some areas of the City where high groundwater tables exist. 6 7. sr834 CULVERTS A culvert is a drainage pipe used to convey a stream through a road or embankment or may carry a stream for a long distance underground to a surface discharge location. Bottomless Culvert - Three Sided Double Reinforced Concrete Box Culvert (RCBC) Bottomless Culvert Arch Corrugated Metal Pipe (CMP) Its installation does not require a large quantity of pipe. 7 8. sr834 Corrugated Aluminum Pipe Arch (CAPA) Driveway Culvert High Density Polyethylene Pipe (HDPE) Reinforced Concrete Pipe Culverts are generally short in length and open at both ends and often must withstand substantial traffic loads 8 9. sr834 DITCHES Ditches are constructed to convey water from storm runoff to an adequate outlet. A good ditch is shaped and lined using the appropriate vegetative or structural material and does not cause flooding, erosion, or sedimentation. Energy dissipating structures to reduce velocity, dissipate turbulence, or to flatten flow grades in ditches are often necessary. 9 10. sr834 Importance to Maintenance & Water Quality Efficient disposal of runoff from the road will help preserve the road bed and banks. Well vegetated ditches slow, control, and filter runoff providing an opportunity for sediments to be removed from the runoff water before it enters surface waters. In addition, a stable ditch will not become an erosion problem itself. This will help alleviate roadway flooding, reduce erosion, and thus reduce maintenance problems. 10 11. sr834 Types of ditches 11 12. sr834 Rounded V-Shaped Ditch U-Shaped Ditch COMMON DITCHs SHAPE EXAMPLES 12 13. sr834 GUTTER THAT PORTION OF THE ROADWAY SECTION ADJACENT TO THE CURB WHICH IS UTILIZED TO CONVEY STORMWATER RUNOFF. A COMPOSITE GUTTER SECTION CONSISTS OF THE SECTION IMMEDIATELY ADJACENT TO THE CURB Rain gutter, a narrow trough or duct which collects rainwater from the roof of a building and diverts it away from the structure, typically into a drain. Street gutter, a depression which runs alongside a city street, usually at the curb and diverts rain and street- cleaning water away from the street and into a storm drain 13 14. sr834 Street gutter Rain gutter The gutter also helps to reduce erosion, prevents leaks in basements and crawlspaces, protects painted or stained surfaces by reducing exposure to water, and provides a means to collect rainwater for later use. A curb and gutter forms a triangular Channel that can be an effective hydraulic conveyance facility which can convey runoff of a lesser magnitude than the design flow without interruption of the traffic. Where curbs are used, composite gutter sections can be effective at increasing gutter capacity And reducing spread on the pavement 14 15. sr834 Drop inlets A location where storm water runoff from an open area enters the storm drain system. Drop inlets are usually part of the public drainage system, but can sometimes be considered private. 15 16. sr834 Types and uses of drop inlets Inlet 24x24 Yard drain Inlet(multiple grate) In driveways &parking where water is intersepted over a large area 16 17. sr834 Catch Basins A catch basin is a structure in the form of a chamber which is provided along with the sewer line to admit clear rain Water free from silt, grit, debris, etc, into the combined sewer. Catch basins allow rainwater runoff to be safely collected to prevent road and property flooding. Catch basins are designed specifically for capturing and conveying stormwater. These are small masonry chamber (75 to 90 cm in DIA. And 75 to 90cm deep)which are constructed below the street inlet to prevent the flow of grit, sand, etc, in the sever lines. When stormwater enters these basins the grit, sand etc, settle down in the bed and the storm water free from all the enters the sewer. The outlet pipe of the catch basin is fixed 60 cm above the bottom (see pics). The outlet pipe is provided with a trap to prevent the escape of odours from the sewers to the catch basins. 17 18. sr834 18 19. sr834 Catch Basin Types & Uses Catch Basin Uses Catch Basin Type 1 With Catch Basin Type 1 (Special) Concrete Medians Curbed grass medians On Curb and Gutter where it does not protrude into the travel lane Catch Basin Type 1 (Special) Concrete Medians Curbed Grass Medians Catch Basin Type 9 In Ditches Outside of the Clear Zone In Low Areas Outside of the Clear Zone 19 20. sr834 In ditches, valleys or low areas where pedestrian traffic is unlikely Not to be used in the path of vehicular traffic Catch basin type 14 Median ditches on dual lane roadways w/earth median Side ditches on controlled access highway Low areas on controlled access highways where there should be no pedestrian traffic In paved medians with concrete median barrier May be a single basin or double basin Catch Basin Type 15 20 21. sr834 On curb and gutter Roadways On valley gutter sections with the face of catch basin at the back of paved lip On curb and gutter roadways On valley gutter sections with the face of catch basin at the back of paved lip Catch Basin Type 16 In low point on curb and gutter roadway In low point on valley gutter sections with face of catch basin at the back of paved lip Catch Basin Type 17 Catch Basin Type 18 21 22. sr834 Catch pits should be provided in the following sections- When the sewers are laid at very small gradient, and the velocity of flow is less than self cleansing velocity. At such situations as the solids present in the sewage will not move and go on accumulating and will require continuous cleaning and maintenance of the sewer, which can be reduced by providing catch basins. When the drains are passing along the water bound macadam road or in sandy area and the market(where lot of defuse is dropped in drains).Because in such areas if all the solids moving in the sewage are allowed to enter the sewage, they will choke the sewer line. The catch basin collects the solids from the storm water. These solids are to be removed at frequent intervals for the proper functioning of the catch basins, otherwise they will block the passage of storm


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