Editor: I am all for recharge basins – if done right. The recharge basins put in by the county and engineered by Nick Hont near Valle Vista are great examples of properly placed recharge basins. They receive water from undeveloped basins and are located near the mountain front.
I am concerned about the location of the proposed Mohave Wash/Rattlesnake Wash recharge basin location for two reasons. First, Mohave Wash drains the basin where there is all the urban development of the hilltop area, and second, it’s located relatively far from the mountain front.
Urban development has all the toxic substances related to modern living; hydrocarbons from spilled fuel, pesticides from home pest control and fugitive garbage. Have you been fueling your car and watched a hose overflow spilling diesel or gas on the ground? Have you heard of a weekend mechanic that dumps his used oil in the alley behind his house, or have you seen the garbage along the drainage channel north of the new Safeway? Where do you think this toxic material goes?
Many of the newer developments have stormwater retention basins like the one at the hospital but there’s still a lot of water that runs off and enters the drainage. Notice the black ring in the hospital detention basin and you get an idea of what flows into Mohave Wash.
Secondly, the location of the proposed recharge basin is located relatively far from the mountain front. As mountains erode, the coarser material is deposited near the mountain front because it’s a high energy environment and the finer material, silt and clay, is carried farther into the basin. Coarse material will accept recharge water easily. The location of the proposed recharge basin is in an area of fine-grained material. A check of the driller’s logs from that part of the basin, such as well 55-228109 , suggests the dry-well injection sites of the recharge basin will hit alternating layers of clay, sand and gravel to 1060 feet depth. The water that enters the dry-wells, drilled to a depth of +/-100 feet, might never reach the aquifer. Instead, they could form perched water tables in the sand between the clay layers. This water won’t add to the main aquifer and thus be ineffective.
We need recharge basins but I suggest they should be placed properly; receiving water of suitable quality with a good chance of the water reaching the aquifer. I hope the engineers that studied the placement of the proposed Mohave Wash/ Rattlesnake Wash recharge basin took these concerns into account.
