SU0002741 SSNL - Laserfiche WebLink

Home Browse Search

On site sources of nitrogen: Feed storage areas: The feed storage area has been paved with asphalt paving. There is no drain system at this point. The runoff simply collects at the low point to evaporate and percolate into the upper soil layers. 1 recommend that this area be tied into a future tail water system. Domestic septic systems: The human waste septic systems are considered to be insignificant. Reference soil suitability study submitted by Valley Ag Research. Corral runoff: Corral runoff at this time flows to evaporative areas. Agricultural liquid waste storage pond: This existing waste storage lagoon is approximately 30 feet deep. The soil boring and subsequent soil tests indicate that there has been lateral percolation of the manure water, but no movement downward towards the ground water. Moreover,the ground water depth in the area is approximately 80 feet below grade. In consideration of the soil type, rainfall and irrigation application rate,there is no threat to the ground water. Agricultural solids storage areas: There are several areas where manure from cattle lanes is being scraped to shallow collection lagoons. These areas have had no special preparations to prevent percolation into the upper layers of the soil. My evaluation is that there is no threat to the ground water from percolation. There may be a slight possibility that surface runoff from a heavy rainfall event could reach the areas' drainage system which will eventually reach the Lone Tree Creek. Impact to Underlying Groundwater/Impact to downgradient wells: In all considerations to the groundwater,the conclusion from the soil borings demonstrate that the soil profile has layers of clay that have prevented the downward movement of surface water. Moreover, the depth to static water table is beyond the penetration of surface water. The chemical analysis of the nitrate content of the soil profile from boring MDS-1 indicates that the nitrates have not penetrated beyond the 35' depth. Three water supply wells were sampled to determine the baseline nitrate concentration. Two of the wells were located on the property at the Manuel Da Silva residence and at the dairy. The third well sampled was the John Da Silva dairy well which is situated approximately one half mile southeast of the Manuel Da Silva dairy. This third well is upgradient from the two wells on the subject property. Water samples from these three wells were transferred under chain of custody to Geo Analytical Laboratories in Modesto. They were analyzed for nitrate, using EPA method 300, with a detection limit of 1.0 mg/liter. The results show that nitrate is present in all of the samples,ranging from a low of 18 mg/liter in the John Da Silva well to a high of 21 mg/Liter in the Manuel Da Silva residence well. Although the presence of nitrate in the ground water indicate that there may be some agricultural contribution contamination, all of these values are well below the maximum contaminant level for drinking water established for nitrate of 45 mg/Liter. Furthermore,the consistent level of nitrate in the ground water indicates that the nitrate in these waters is more a result of a regional infiltration into the water table,rather than contribution from the local source of the Manuel Da Silva dairy operation. It is concluded that the proposed dairy expansion will not impact the downgradient ground water. There is a possibility that there could be surface contamination of Lone Tree Creek via the site drainage system. The source would be from field, feed storage areas and or corral runoff. It is important that this facility have a construction program that prioritizes the timing of a drainage system at a time that will prevent such offsite runoff. 11