pf_01977 - Laserfiche WebLink

Home

I I I I I I I I I I I I I I V I I. .ulJLJIJES A. .s~~_t911~~:tl~D_fa~lljI1~.s A computer progran was developed usl ng the "grav Ity sanl tary sewer des I gn and constructIon" manual requl rements as prepared by the American Society of Civil Engineers (ASCE) and the Water Pollution Control federation (WPCF). Available Information regardIng current and proposed future sanItary sewer and water flows for the sanItary sewer service area was utilized. Currently, the 11ft station at the southwest corner of County Road C and Snel ling Avenue, whIch serves the area, Is calculated as pumpl ng an average of 0.133 mgd compared to th eO. 159 mgd figure as estimated by the ASCE program under existing condl tl ons. Future flow conditions were estimated based on ful I development of the service area and the addition of the life and Health Fitness Center and the new residence hall at Northwestern CoI lege. Because of the flat slope on the stretch of the sa n I tary sewer Just dow-nstream of the current Northwestern College servIce lIne which lImIts the pipe capacity, the life and Health FItness Center Is proposed to connect to the exIstIng sanItary sewer line at the next downstream manhol e as shown on Exh I bIt G. The total peak flow Is estimated based on multiplying the cumulatIve flow by a peak factor determIned by the cumulatIve equivalent population. As population Increases, the peak factor w I II decrease. The future flow predictions show two areas where total peak flow Is predicted to be larger than existing capacity. The sanitary sewer flow Just downstream of Russell Court and the Northwestern College area along Lydia Avenue, Is estimated to have a peak flow 2% greater than capacity. The next line downstream, startl ng 300 feet west of Russell Court, Is estl mated to have a peak flow 8% greater than capacIty. We do not expect any problems to arise fran these predIctIons for several reasons: 1. Our predicted f lows tend to be very conservative. All flows used In the calculatIons are the highest to be expected. 2. Full development of the area, IncludIng full use of the sewer system, may never occur. These two reasons probably account for our predIcted current flow beIng 20% less than the actual calculated flow. .. 3. Pressure flow for a very short perIod of time should have a nagl igible Impact on the system. ...,.15- 8621 ~