The picture to the right is an excellent demonstration of berms channeling water into a pond. Photo credit: NRCS.
The pond shows a man made dam. This is an excellent use of the lands natural topography to hold surface water and minimize the need for pumped ground water.
Notice the extensive development of the riparian area around the creek, near the bottom of the dam.
The following charts simulate the levels of stored water in the proposed system of ponds. Scenarios for the water levels are based on NOAA rainfall data for Central Texas (mm/hr) over a period of 2000-2013. The data also incorporate assumpations about the evaporation levels in Central Texas. The worst years for drought were from 2007-2013, a period which has been repeated for 2014-2020 in the graphics.
The following impacts were tested on the rainwater storage model (household water bills were assumed at 7,000 gal/month):
- Low Flow toilets
- Low Flow shower heads
- Grey water recovery
- Black water recovery
The combined benefits of the above strategies resulted in going from 25.6% capacity utilization of the ponds over a 12 year period, to 27.8% or a 2.2% increase.
The following section assumes all of the benefits of these household measures, but then addresses the improvements to be gained by reducing the evaporation rates.