Soak Pits

http://www.rainwaterharvesting.org/urban/Design_Recharge.htm

http://www.slideshare.net/indiawaterportal/rainwater-harvesting-and-groundwater-recharge-in-urban-centres-experiences-from-the-field-biome-solutions

http://www.tn.gov.in/dtp/rainwater.htm

http://www.rainwaterharvesting.org/Urban/Components.htm

Dear Siga
Try the following: <http://www.cee.mtu.edu/peacecorps/reports/Brooke_Ahrens_Final_Report.pdf

A Comparison of Wash Area and Soak Pit Construction:

The Changing Nature of Urban, Rural, and Peri-Urban Linkages in

Sikasso, Mali

By

Brooke T. Ahrens

MICHIGAN TECHNOLOGICAL UNIVERSITY

2005

All excellent comments. Knowing the composition of the earth and the location of the pits relative to utilities and water supply is important. I would add these minor caveats:

1. Learn something about the percipitation - quantity and loading rate. This will have a direct effect on the size and number of soak pits.

2. Learn something about the surface use of each area that is tributary to a soak pit. Impervious surfaces, such as concrete, building roofs, etc. increase the rate and volume of runoff significantly. Open fields and woods tend to soak up a lot of rainfall.

3. Learn something of the surface flow patterns and position the soak pits accordingly. Try to position them so that they are equally loaded, or change the storage volume and infriltrating surface accordingly.

The comment was made in a previous reply that I concur with. If the flooding is occuring because a tributary tops its banks every time it rains, then protection from this type of flooding is different than water that pools in the area because it is raining faster than it can soak into available pervious ground.

Good Luck. It sounds like a beneficial and fun project to work on.

The things you need to do-

1. prepare a concept level study, this study should identify a number of conceptual level alternative locations where percolation facilities may be viable. The study should review availability of lands, any available soils, geologic and hydrogeologic mapping and information, local groundwater mapping and information, general area topography and drainage features (both municipal and natural). The Study should determine vaibility of alternatives based on this preliminary information, on the basis of estimates of percolation rates and required sizing of concept facilities (how much land is necessary and how deep), induced flooding, groundwater mounding impacts, water quality impacts and separation requirements, cost of lands aquisition and development, connections to local municipal drainage conveyance, proximity and risk from or impacts to local natural drainage features.

2. conduct site specific studies to evaluate the alternatives for viability, such studies might include preliminary geotechnical and hydrologic/geologic studies, preliminary land surveys, and planning/land use and title reviews.

3. reduce the alternatives to those sites deemed viable under the specific alternatives studies. There should be a very few alterntative sites at this point, for each percolation facility (less than 3, possibly even only 1)

4. Prepare a design concept for each facility at each viable alternative.

4. conduct site specific environmental review studies of the remaining viable alternatives and the concept design.

5. conduct concept-specific site-specific studies, particularly geotechnical, hydrologic/geologic and land surveying that are specific to the design concept as modified with environmental mitigations

6. prepare a design based on the design concept, findings of studies and resultant engineering parameters, and environmental mitigations. Prepare construction contract documents

7. negotiate land acquisitions and acquire lands.

8. go to bid and retain contractors.

9. build facilities

First instruction set: The best places are these spots in the puddles where after the rain your feet (dis)appear the most under water. Plant a nice flag there to drill later.

Do not use soak pits in this situation. Use Evapotransipration with flEXible pipes with 0.5 mm diam holes, WUT PIES PLACED on the ground. Use in heaVILY TREED AREAS TO ALLOW THE WIND, LEAF DEMAND AND ROOT DEMAND TO TAKE UP THE MOISTURE