Trench infiltration for managed aquifer recharge to permeable bedrock

Abstract

Abstract:Managed aquifer recharge to permeable bedrock is increasingly being utilized to enhance resources and maintain sustainable groundwater development practices. One such target is the Navajo Sandstone, an extensive regional aquifer located throughout the Colorado Plateau of the western United States. Spreading-basin and bank-filtration projects along the sandstone outcrop's western edge in southwestern Utah have recently been implemented to meet growth-related water demands. This paper reports on a new cost-effective surface-infiltration technique utilizing trenches for enhancing managed aquifer recharge to permeable bedrock. A 48-day infiltration trench experiment on outcropping Navajo Sandstone was conducted to evaluate this alternative surface-spreading artificial recharge method. Final infiltration rates through the bottom of the trench were about 0Ð5 m/day. These infiltration rates were an order of magnitude higher than rates from a previous surface-spreading experiment at the same site. The higher rates were likely caused by a combination of factors including the removal of lower permeability soil and surficial caliche deposits, access to open vertical sandstone fractures, a reduction in physical clogging associated with silt and biofilm layers, minimizing viscosity effects by maintaining isothermal conditions, minimizing chemical clogging caused by carbonate mineral precipitation associated with algal photosynthesis, and diminished gas clogging associated with trapped air and biogenic gases. This pilot study illustrates the viability of trench infiltration for enhancing surface spreading of managed aquifer recharge to permeable bedrock. Published in

Variably saturated groundwater modelling for optimizing managed aquifer recharge using trench infiltration

“…To date, the only published trench infiltration rates to permeable bedrock are from a pilot‐scale study of the Navajo Sandstone of southwestern Utah (Figure ). This work was done to test its effectiveness as an alternative to surface spreading currently being implemented beneath Sand Hollow Reservoir for delivering managed aquifer recharge to the sandstone (Heilweil and Watt, ). During the trench infiltration experiment, infiltration rates per unit metre of trench decreased from 1.77 m/d at the beginning of the experiment to 0.38 m/d at day 48 (Table and Figure of Heilweil and Watt, ).…”

“…This work was done to test its effectiveness as an alternative to surface spreading currently being implemented beneath Sand Hollow Reservoir for delivering managed aquifer recharge to the sandstone (Heilweil and Watt, ). During the trench infiltration experiment, infiltration rates per unit metre of trench decreased from 1.77 m/d at the beginning of the experiment to 0.38 m/d at day 48 (Table and Figure of Heilweil and Watt, ). From about day 5 through day 30, the infiltration rate remained relatively constant at 0.5 m/d; the steady rate during this 25‐day period was likely after the initial wetting‐up period and prior to hydraulic connection with the regional water table.…”

“…Map showing Sand Hollow basin and the infiltration trench experiment site. Modified from Heilweil and Watt, …”

Assessment of managed aquifer recharge at Sand Hollow Reservoir, Washington County, Utah, updated to conditions through 2014

“…Sand Hollow has been the subject of interdisciplinary, cooperative investigations of groundwater hydrology and geochemistry since 1999. Previous Sand Hollow reports document pre-reservoir vadose-zone and groundwater conditions prior to March 2002 Heilweil and others, 2006;Heilweil and others, 2007;Heilweil and others, 2009b), pond and trench infiltration studies adjacent to the reservoir (Heilweil and others, 2004;Heilweil and Watt, 2011), and post-reservoir groundwater conditions, water budgets, and estimates of groundwater recharge from the reservoir from March 2002 through December 2012 (Heilweil and others, 2005;Heilweil and others, 2009a;Heilweil and Marston, 2011;Marston and Heilweil, 2013). These reports also contain monitoring-well and production-well completion information, as well as historical water-quality and precipitation data.…”

Managed aquifer recharge via infiltration ditches in short rotation afforested areas

“…Managed aquifer recharge encompasses a series of strategies and techniques for increasing percolation towards an aquifer, using excess flows in streams or channels, agricultural return flows or treated waste water (Bouwer, 2002;Greskowiak et al, 2005;Prommer and Stuyfzand, 2005;Massmann and Sültenfuß, 2008;Heilweil and Watt, 2011).…”