SU0004495 SSNL - Laserfiche WebLink

Home Browse Search

The actual septic tank size, the number of Infiltrator Chambers or conventional leachlines, and the number of seepage pits are unknown at this time since there is no plan to develop the property with residential units (primary and possible second unit dwellings). According to the San Joaquin County Sewage Standards, each new system must have at least a 50% standby replacement area incorporated into the design. All related septic system structures and the new domestic wells must comply with the published "distance" requirements from property borders, roads, irrigated fields and irrigation pipelines, etc. It is important to note that all septic systems have a lifespan, which is dependant on several factors and is therefore difficult to determine. Septic system leachline failure would primarily result from the advanced formation of a "biomat" or"clogging mat" on the wetted soil/effluent interface. This mat is composed mostly of aerobic and anaerobic bacteria and bacterial products consisting of a slime of polyuronides and polysaccharides. If the soil/effluent interface is well aerated, a variety of soil microfauna such as nematodes and protozoa may digest the clogging mat bacteria to some extent. Since the shallow subsurface soils consist of a clay soil material, anaerobic conditions may prevail over time which may shorten the life of the leachfield. However, if Infiltrator Chambers are installed high in elevation, there will be a greater opportunity for oxygen intrusion from the atmosphere, thus theoretically assisting in biomat decomposition. The on-site domestic well was sampled and tested as rewired by Mike Huggins of EHD_ After the test results were obtained for this domestic well, Mr. Huggins requested the testing of the irrigation wells. However, due to the autumn time of the year and the recent rains, all five of the irrigation wells have been shut down. Consequently, it was decided by Mr.Huggins_that any new well drilled on the subject property must have a minimum 200-foot grout seal. In addition, it will - H1 be an EHD requirement to test the water from each individual well below this grout seal before completion of the well. If nitrates and/or DBCP concentrations are found approaching, or over the MCL in the tested water, the affected well may have to be drilled deeper and the grout seal also extended to a deeper depth. Regardless of the nitrate concentration ultimately determined in any new domestic well, bottled water should always be used for drinking and cooking purposes. In discussions with Mr. Robert Longstreth after obtaining the water test results, it was conveyed to him that the on-site domestic well would have to undergo significant filtration for both nitrate and DBCP to achieve acceptable potability. Consequently, he has agreed to close-in (destroy) this domestic well under EHD permit. In all likelihood, the high DBCP concentrations found in the shallow depth domestic well originated from the subject property being planted in vineyard production during the 1970s when DBCP was used extensively in vineyards throughout the San Joaquin Valley. The high nitrate concentration originated from agricultural production of the subject property and upgradient surrounding properties over the past number of decades. Page -5- Chesney Consulting