Paper: Recharging Aquifers by Capturing Flood Flows - Texas Case Study

Good stuff from Qian Yang and Bridget R. Scanlon in this informative paper, How much Water can be Captured from Flood Flows to Store in Depleted Aquifers for Mitigating Floods and Droughts? A case Study from Texas, US, Environmental Research Letters, Volume 14, No. 5.

Click on the article title to access the online version with its links and supplemental information.

Here is a popular description of the project.

Abstract
Extreme flooding from Hurricane Harvey (~100 km³, ~80 million acre feet, maf of rainfall) in Houston, Texas, US co-located with depleted aquifers raises the question of whether we can capture floodwater to reduce flooding impacts and replenish aquifers for droughts. Here we quantified how much water could be captured from high magnitude flows (HMFs) in 10 major rivers discharging to the Gulf of Mexico for potential storage in depleted aquifers along the Texas Gulf Coast. Results show that HMFs (≥95th percentile) from rivers discharging to the Gulf of Mexico total 37 km³ (30 maf) in 2015–2017, similar in capacity to US Lake Mead (32 km³, 26 maf). These flows are less than modeled unappropriated flows that consider appropriated water rights and limited analysis suggests moderate reduction from environmental flows. Similarity in high flow volumes and modeled groundwater depletion in the Gulf Coast Aquifer system (~25 km³, 20 maf) underscores the potential to partially mitigate flooding using aquifer storage. Interim storage would be required to resolve disconnects between high flood intensities and low aquifer injection rates. Engineering approaches will become increasingly important to manage climate extremes.

Conclusions
The challenges of floods and droughts to water resource managers can be partially mitigated by storing HMFs in surface and subsurface reservoirs, as evaluated for the Texas Gulf Coast region. Estimated HMF volumes exceed modeled unappropriated water rights. Capturing an estimated 65% of HMF flows should not impact modeled environmental flow requirements, using the San Antonio and Brazos basins as case studies. The total HMF volume during the last three wet years (37 km³; 30 maf, ~2 times state water use, 2015–2017) is sufficient to replenish the depleted Texas Gulf Coast Aquifer system (~25 km³, ~20 maf). The inverse exponential relationship between number of HMF events and HMF duration and volume is favorable for aquifer storage as low numbers of long duration events (e.g. ≥1 week) contribute most (80%) to HMF volumes based on the past 50 years record. Capturing HMFs and storing them in these depleted aquifers will require additional wells for storm water management and aquifer storage and recovery in the Texas Gulf Coast region. In addition to quantifying the potential water volumes that can be captured from HMFs, this study highlights many of the additional factors that need to be considered, such as water rights and environmental flows, to assess the feasibility of subsurface storage of flood waters.

We're thinking along the same lines based upon our MAR work in the Yakima Valley, WA.

Enjoy!

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Comments

[Michael]

Thanks!