Two father son teams come to mind when water is mentioned in our area, Stephen Brown and Chuck Brown with the Upper Colorado River Authority and former San Angelo Water Chief Will Wilde and his son Blake. The Brown team appeared before City Council last week to propose a water project involving the Red Arroyo. UCRA Director Chuck Brown led the presentation.
Very early on we realized the Red Arroyo is a significant water producer. Through Tarleton's modeling efforts and our on the ground monitoring stations, we realized that pretty much every time we had an inch rain in San Angelo the Red Arroyo produced about 500 acre feet of water. So, theoretically in our average rainfall year, which would be 20 inches of rain, the Red Arroyo could produce upwards of 10,000 acre feet of water, which is annually 2/3rd's of the City of San Angelo's municipal water usage.I've only lived here since 1994 but I've never seen twenty one-inch rains in one of those twenty years. I instantly was curious as to how Red Arroyo water flows varied from the average. What might they be in wet years vs. dry?
Brown and the UCRA recommended building a stormwater storage basin near the bottom of the Red Arroyo watershed. Their slide stated:
Approximately 11,550 acre-feet will be captured by the basin in an average rainfall year.Yet the city only has water rights to 5,000 acre feet in any one year. UCRA Consultant Stephen Brown said that 5,000 acre feet for the City is "guaranteed almost every year." This assertion quickly came under challenge.
A respected consultant modeled the City's take from the Red Arroyo using San Angelo's sixty year rainfall record and the 5,000 acre feet restriction. His projections showed the City's take varying from near zero to 4,900 acre feet in any given year.
Chuck said the project would cost roughly $20 million. Yet his "Opinion of Probable Cost" slide mentioned a much higher figure (in the notes section):
The preliminary cost estimate to construct a storm water basin to provide a storage volume of 2860 acre-feet and the infrastructure for transferring the captured water to the treatment plant is $76.9 million. The cost estimate assumes that the high powered and low powered electrical lines running across the site will be relocated as part of the construction. The single largest contributing factor to the cost is the excavation cost at 60% of the total estimated cost.
After hearing all the presentations, the situation is as clear as the Red Arroyo after a heavy rain. City Council faces two studies on water, a deeper geotechnical/engineering study on the Red Arroyo project and a reclaimed water use study.
Reclaimed water brings to mind the other father-son team, Will and Blake Wilde. Former Water Chief Will Wilde's hobby cotton farm benefits from reclaimed water, which is solely purposed for irrigation. Wilde arranged the deal and successfully defended it in dry years. Might the Red Arroyo save reclaimed water for hobby cotton farmers? Time and rain will tell.
Correction: I erred in giving Stephen Brown the moniker for his son Chuck in the original version of this piece. My apology.