Where to Recharge

Within the Los Angeles River watershed, groundwater supplies are augmented through several means. These are:

  1.  Incidental recharge where rain and irrigation water infiltrates through softscapes and reaches potable aquifers
  2. Distributed recharge where private and public development projects construct “best management practices”, or BMPs (Water Quality Improvements), to control and infiltrate stormwater in areas where the water can reach the potable aquifers
  3. Centralized recharge where large singular projects are constructed to specifically capture stormwater for groundwater recharge, usually through surface spreading or injection directly into the potable aquifers.

Expanding upon analyses conducted for the Los Angeles Department of Water and Power’s Stormwater Capture Master Plan, all areas within the Los Angeles River watershed were categorized by how well stormwater could infiltrate into underlying potable groundwater aquifers. Three geophysical categories were created based on multiple physical data sets, including soil type, underlying geology, groundwater aquifers, depth to groundwater, and slope, as shown in the figures below.

 
 
 
 
 

These spatial data were overlaid in order to assign each area of the watershed one of the following geophysical categories, as shown in the figure below:
• A-areas most conducive to infiltration to a potable aquifer,
• B-areas somewhat conducive to infiltration to a potable aquifer, and
• C-areas least conducive to infiltration.


There were also anthropogenic obstacles that were considered in the analysis, where infiltration practices should be currently limited, but may be resolved over time. These include areas of polluted groundwater, and areas with severely polluted runoff (such as from heavy industrial activities) Areas with anthropogenic obstacles were assigned to Category C, the least conducive to infiltration practices.