Query 1: In our project a bigger chunk of the land has been kept as an open ground as per mandate from the MP government. Can we exclude this ground from our overall site area calculation since our calculations regarding landscape, Heat island effect, rain water harvesting are getting affected. This entire ground will be kept open and it will be filled with soil only.
Query 2: Criterion 18: Rain Water Harvesting: The project site has a rocky terrain and because of this Rainwater recharging is difficult.Consequently for 37 acres of site area runoff is very large. Please suggest how this can be addressed.
Reply 1: This area can be excluded from the registered site area if it is not used as a service area for the project registered as parking/playground, etc. If the site area is modified, the project team has to make sure that consistent area is considered throughout the project calculations across various criteria for rating.
Reply 2: This is a consultancy query, please contact your consultant for suggestions. However following tips can be used when discussing with the consultants:
Rain water can be handled in 3 ways on site and each of these strategies in combination has many parameters to be looked before proposing -
Conducting hydro geological study of the site ( very essential in case of large site areas)
Post monsoon water table
Soil percolation capacity ( for a large site specially with rocky profile there are chances to find fishers which can be easily used as good water holding & percolation points.)
Rainfall considered (for optimum system working do consider average (3-5 years) of peak hourly rainfall data to calculate the runoff from site)
Run off calculation ( considering correct run off coefficient)
Desilting /grease traps (workable design as per site)
Recharge section (workable design as per site)
- Storing and reuse
Segregation of roof runoff and site run off
Storage tanks capacity ( the raw water/treated water tank can be used with proper system)
Rainfall considered ( Use average ( 3-5 years) of peak daily )
- Delaying the run off (one of the most easiest, cost friendly )
Landscaping elements (such as open channels,swales, collection ponds etc.) to hold the water and delaying the run off to drains
Reducing hard paving as much as possible.
This combines the concepts of recharging and storing in natural grounds.
A combination of all of the above strategies can be implemented in each site with the correct process in place. If not designed considering these site parameters it results in high risk urban flooding.