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 Water for DFW – Building-scale rainwater harvesting vs. Marvin Nichols

Posted August 7, 2014 by waterbloguer

In the last post we reviewed the potential of building-scale rainwater harvesting (RWH) as a water supply strategy in the high-growth area around Austin, in Central Texas. Here, we examine its potential in another high-growth area of Texas, the Dallas-Fort Worth area, commonly called the Metroplex. And then we will contrast that strategy with doubling down on the watershed-scale rainwater harvesting strategy, as may be represented by the proposed Marvin Nichols Reservoir.
To gain an appreciation for the potential of building-scale RWH in and around the Metroplex, modeling was executed for the following locations: Athens and Terrell to the east-southeast, Ferris closer in to the south, Cleburne to the southwest, Weatherford to the west, Bowie to the northwest, Sherman to the north-northeast, and Denton closer in to the north-northwest. Ringing the Metroplex, these locations offer an overview of conditions all around it.

s was the case for the modeling results of the Central Texas locations, it was seen that “right-sized” building-scale RWH systems around the Metroplex would have provided 97-99% of total interior supply through the recent drought period for houses modeled with a presumed average water usage rate of 45 gallon/person/day. But around the Metroplex, the “right-sized” systems would be somewhat smaller than would be required around Austin. Recall that the “right-sized” system there to serve a 4-person household would be a roofprint of 4,500 sq. ft. and a cistern volume of 35,000 gallons. In Bowie, Weatherford and Cleburne, the “right-sized” system for a 4-person household would require only 3,750 sq. ft. of roofprint, paired with a 25,000-gallon cistern in Cleburne and Weatherford and a 27,500-gallon cistern in Bowie. All other locations would require 3,250-3,500 sq. ft. of roofprint and 20,000-25,000 gallons of cistern capacity. It is expected that a one-story house plan with a 2-car garage plus a “typical” area of covered patios/porches could provide a roofprint of 3,000-3,500 sq. ft., so these modeling results indicate many houses in/around the Metroplex would not require any “extra” roofprint to be added on.....>>>