Increasing Sustainability in a Heavily Stressed Region of Gulf Coast Aquifer by incorporating Managed Aquifer Recharge in Houston, Texas
Abstract
Houston is one of the most populous cities in the United States. Use of groundwater for public supply and industries increased by 2% and 8%, respectively, between 2018 and 2019. Due to increase in population and industrialization, extraction of groundwater has increased which has led to land subsidence in the region. As a result, the metropolitan region of Houston is frequently flooded, most recently by Hurricane Harvey. The effects of these hydrological extremes could be mitigated by adopting Managed Aquifer Recharge techniques. Four test cells have been delineated in an existing detention basin. Enhanced Infiltration Systems namely amended soil, trench aggregates and a proprietary system have been set up in three of the test cells; the fourth cell has control condition. These systems have been monitored for their response to subsurface variables such as groundwater levels, soil moisture, and drainage rate. Trenches yield the maximum recharge; the groundwater level is 1.5 m higher under the trenches when compared with the control cell. The soil moisture content closer to the surface increased by a maximum of 200% in amended soil after Tropical Storm Beta. This suggests that it can retain more soil moisture and is favorable for shallow rooted vegetation. The proprietary system outperforms others as far as soil moisture in deeper levels is concerned. The TDS concentration is found to be 2720 ppm in groundwater underlying trenches though it is within the Texas drinking water standard (< 1000 ppm) for amended soil and control condition. All the aforementioned results were obtained from small and large storm events that occurred over the course of 2 years. It is interesting to note that the groundwater levels under the trenches, amended soil, and control test cells were uniform when the entire basin was under 1 feet of water owing to incessant rainfall during the summer of 2021. This study demonstrates that the enhanced infiltration systems contribute more recharge even during small storm events thus rendering them helpful throughout the year. It was also observed that the control test cell promotes more recharge only when water is ponded in the basin. The water content in the soil pores under control test site is lower when compared to trenches and amended soil year-round thus facilitating more recharge at the time of basin inundation.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H15L1171M