ARCHIVED REPORTS_DRAFT ENVIRONMENTAL IMPACT REPORT

Home Browse Search

Table 30: Oxygen Demanding Substances and Loads from the WQCF for Increasing ADWF Flowrate BODS Ammonia TUOD GTUOD(1) Modeline Anuroach Minimum Dissolved Oxveen: The Streeter-Phelps model is used to (MGD ADWF) (mg/L) (mg/L as N) (Ib/d) (Ib/d) estimate the DO sag downstream of the WQCF discharge. Only the minimum DO downstream of the discharge is calculated for the present analysis in order to evaluate the impact of the 6.0 20 22 7,537 project above the currently permitted discharge. The model is a function of the BOD.It and DO 8.11 20 2 4,002 -3,535 concentrations,flowrates,temperature,and the BOD decay and reaeration rates. The R-1 and 9.87 EDAW 2000 20 2 4,871 -2,666 effluent information are available from the near-field analysis. The rate of BOD decay can be 9.87 Current 7 1.5 2,006 -5,531 selected from previous modeling efforts. The reaeration can be estimated as a function of river 17.5 7 1.5 3,557 -3,981 depth and velocity. The detailed Streeter-Phelps analysis is presented in Appendix B. 27 7 1.5 5,487 -2,050 Monthly values used to perform the Streeter-Phelps analysis are listed in Table 32. The near (1)ATUOD is the difference between loading at listed WQCF flowrate and TUOD load for 6.0 MGD(ADWF)case for use in field analyses R-1 concentrations of 5.26 mg/L BODS and 0.13 mg/L as N ammonia are utilized the regression model. in the DO analyses. Note that considering the seasonality of ammonia does not affect the results appreciably and therefore the higher summer value is used as a conservative number for the minimum DO analysis. During the summer,the San Joaquin River is supersaturated with Results for DWSC DO: The regression model is used to estimate future DWSC DO oxygen during the day,presumably due to algal photosynthesis. concentrations for projected ADWF discharge rates in relation to DWSC DO that would have occurred when the WQCF permitted capacity was 6.0 MGD(ADWF). For example,if a certain Table 32: Monthly Input Values for Parameters in the Streeter-Phelps Dissolved Oxygen Model set of conditions upstream in the San Joaquin River(e.g.temperature,BOD load,etc),and flows and conditions in the delta(e.g.tides,export rates,etc.),combined with a WQCF discharge for Temp. Flowrate Depth Velocity DOsat DOR-1 the 6.0 MGD(ADWF)case result in a DWSC DO of 6.0 mg/L,then under the same conditions, Month (°F) (cfs) (m) (m/s) (mg/L) (mg/L) but with the WQCF discharging under the currently permitted conditions and flowrate of 9.87 Jan 50 2,662 2.9 0.26 11.3 9.3 MGD(ADWF),the DWSC DO would be 6.21 mg/L. The complete suite of DWSC DO and the Feb 53 1,897 2.4 0.22 11.0 8.8 calculated concentration for the future projected WQCF flowrates are listed in Table 31. Mar 58 2,137 2.6 0.24 10.3 8.4 Additionally,the difference between DWSC DO for the projected WQCF flowrates and the - current permitted capacity of 9.87 MGD(ADWF)are included in the table. For both Phase IV Apr 63 2,666 2.9 0.26 9.7 9.1 and V,the DO concentration in the Stockton DWSC will be greater than when the WQCF May 67 2,684 2.9 0.26 9.3 9.1 capacity was 6.0 MGD(ADWF). Jun 72 1,394 2.0 0.20 8.7 10.1 Jul 76 1,220 1.8 0.19 8.4 9.1 Table 31: Modeled SDWSC DO and Change from Currently Permitted Levels Aug 76 1,118 1.7 0.18 8.4 7.2 6.0 MGD 9.87 MGD Sep 71 1,182 1.8 0.19 8.9 8.0 (ADWF) (ADWF) 17.5 MGD(ADWF)-Phase IV 27 MGD(ADWF)-Phase V Oct 65 2,003 2.5 0.23 9.5 7.3 DO in DO in DO in Difference DO in Difference Nov 56 2,091 2.5 0.23 10.5 7.8 SDWSC SDWSC SDWSC from 9.87 MGD SDWSC from 9.87 MGD Dec 49 2,064 2.5 0.23 11.6 8.7 4.00 4.22 4.11 -0.11 4.02 -0.20 5.00 5.22 5.11 -0.11 5.02 -0.20 The resulting total ultimate oxygen demand concentration for R-1 is 13.7 mg/L. As noted above, 6.00 6.21 6.11 -0.10 6.02 -0.19 the future effluent total ultimate oxygen demand concentration is 24 mg/L which represents a 7 7.00 7.21 7.11 -0.10 7.02 -0.19 mg/L BODS and 1.5 mg/L as N ammonia. The initial concentrations of total ultimate oxygen 8.00 8.20 8.10 -0.10 8.02 -0.18 demand where WQCF effluent is well-mixed with the San Joaquin River for each case 9.00 9.20 9.10 -0.10 9.02 -0.18 considered in the project are listed in Table 33. City of Manteca Antidegradation Analysis 75 June 2007 City of Manteca Antidegradation Analysis 76 June 2007