SU0013403 - Laserfiche WebLink

Home Browse Search

To: Mr. Mike Quartaroli Page 3 January 13, 1988 Based on the anticipated size of the treatment plant facilities, it appears that at least 10,000 sq ft should be allocated. More land could be required if the selected site is shaped in an irregular manner, if there are construc- tion interferences, and if it is desirable to maintain a setback of the treat- ment facilities. We would recommend setting aside 15,000 sq ft or more if possible. C. DISPOSAL BASINS The land area required for the basins will be highly dependent upon the per- colation rate into the ground. At this time, little information is available on the percolation rate, so it is necessary to make conservative assumptions. When better data is available, it may be possible to reduce the land area requirements. The required basin area is a function of the amount of wastewater, the amount of precipitation entering the basins, the rate of evaporation, and the rate of percolation. The amount of wastewater entering the basins on an annual basis is about 11.8 ac-ft. The 100 yr annual precipitation, as measured in Stockton, is about 25. 1 in. Average evaporation is about 51 .2 in., but in a year of high precipitation or cool weather, we have estimated that the evaporation would only be 48.5 in. The table on the following page shows required basin area with different per- colation rates. In most cases a percolation rate of 0.01 ft per day would be a conservative estimate. However, lower rates could be realized if the soil contains clay or if wastewater solids are allowed to accumulate on the basin bottom thereby reducing percolation. If groundwater or soil conditions are not suitable for percolation, it is possible that regulatory agencies may only allow evaporation as a disposal mechanism. Required basin area in this case is given in the table on the following page. The table also provides a land area associated with each basin area. The land area is based on a 30 ft wide border around the basins. Basin depth does not significantly affect the required surface area. However, sufficient depth is necessary to contain accumulated water in the winter months when the evaporation rate is low and precipitation is high. In the case where the percolation rate is 0.010 ft/d, a total depth of 4 to 5 ft would be suffi- cient. This would include 2 ft of freeboard. MEL NOLTE andASSOCIATES Engineers/Planners, Survevors