COMPLIANCE INFO_NL STDY - Laserfiche WebLink

Home Browse Search

,r Mr.Jadi Singh January 24,2003 Job Number:LE02481 Page 7 quite mobile in ground water and originates from agricultural fertilizers, dairies, and untreated septic waste_ The total nitrogen analysis indicates a result of 0.9 mg/L as nitrogen(N) (MCL is 10 mg/L-N). Nitrate as NO3 was found to be 4.0 mg/L(MCL for nitrate is 45 mg/L as NO3). The ground water hardness is "very hard" and the Sodium Absorption Ratio (SAR), indicating the danger of high-sodium water for irrigation, is considered medium hazard. No tests for hydrocarbons were performed. The water quality tests were limited to "general mineral" and "total nitrogen." 5.0 PERCOLATION TESTS AND INFILTRATION TESTS 5.1 Falling Head Percolation Tests �- Six falling head percolation test borings were drilled utilizing a 4-inch diameter hand auger and a 6-inch diameter"post hole"digging tool. A two-inch diameter PVC pipe was used for all the falling head percolation tests except for P-4. For the five tests with PVC pipe, the pipe was left open ended on the top and bottom. Perforations were made on approximately the last 12 inches of the casing. Approximately two inches of"pea gravel" were placed in the bottom of the hole, the casing was installed, and the annual space was filled with"pea gravel." For percolation test P-4, an open 6-inch diameter post hole was dug to visually inspect the fall of water in the hole due to rapid conditions. A simple falling head percolation test similar to the r. others was performed. A reference point was established to measure the fall of water. All the percolation test borings were pre-soaked between 48 to 24 hours prior to the percolation tests then supersaturated 4 hours prior to each percolation test and double ring infiltrometer test. A falling head percolation test was conducted on all six percolation test borings. The falling head tests were conducted by adding approximately 6 inches of water above the bottom of the hole. The drop of water was measured for a period of 1 hour or four hours depending on the permeability of the soil. For the 1 hour tests,the fall was recorded each 10 minute segment. For i- rapid conditions,the fall of water was observed until the hole went dry and the time for 6 inches of drop was measured. For the four hour tests,the fall of water was measured every 30 minutes_ *" Under a consultation permit with San Joaquin County Environmental Health Division (Permit No. SR0032000), Mr. Johnny Yoakum R.E.H.S. of that office observed the percolation tests and double ring infiltrometer tests conducted during the afternoon of Monday,November 25, 2002_ The purpose of the consultation permit was to discuss the percolation rate and infiltration rate of e pERSO1 Z � L.r