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Loss and gain measurements made by CDWR in Model Inlet Canal (table :3) showed small losses ranging from I to 5 percent of the h<,adgate inflow (losses within the uncertainty of the measurements). The USGS also found losses and gains in Model Inlet Canal to be within the uncertainty of the mea- surements, with the exception of one reach (MOTO to MOTI) (fig. 13-A2 and table 8). Measurements made by CDWR showed losses of 8, 16, and 18 percent of the subreach inflow to a gain of I percent of the subreach intlow in Model Outlet Canal from M2HG to M3HG (table 8). Downstream from Model Reservoir, along Model Outlet Canal from M2HG to M3HG, the USGS mea- sured canal losses of 30 and 59 percent of the subreach inflow. The large variability in measured losses and gains from M2HG to M3HG may be due to unsteady-flow conditions during the measurement period. The flow may have changed substan- tially in days preceding some measurements. The variability also may be due to length of time the canal was running before the measurements were made. However, because CDWR does not report flow downstream from Model Reservoir at M2HG, there is no record Df daily streamflow available to determine if steady-flow conditions existed before the measurement period or to determine the number of days the canal had been flowing before the measurement. It is interesting to note that the larg- est losses from M2HG to M3HG were computed for measure- ments made in M2.y and June (early in irrigation season), and the smallest losses were determined for measurements made in August (later in the irrigation season). John Flood Canal John Flood Canal diverts water from Model Canal about 2.4 miles downstn:am from the Model headgate. An 8-ft Parshall flume with a free-flow capacity of about 140 ft3/s is used to measure irrigation diversions at the John Flood Canal headgate. Loss and gain measurements were made along John Flood Canal on August 8, 2000, May 24, 2001, June 17,2003, and June 15,2004. Information for individual measurements is summarized in table A6 in the Appendix. Discharge measure- ments were made em the main channel and diversions from the John Flood headgate (JFHG) to the end of the canal at JF25 (fig. 14). Losses and gains for selected subreaches of John Flood Canal are li:;ted in table 9. Figure 14 shows the mea. surement site locadons, and figure 15 shows losses and gains along John Flood Canal in relation to distance downstream from the headgate. On August 8, 2000, discharge measurements were made at main channel and diversion locations from JFHG to JF25 (fig. 14). Three closed diversion gates were noted as having leakage. The total leakage was estimated to be about 0.12 ft3/s (table A6). Flow at the Parshall flume diversion at JFI2 was not measured but was determined using standard Parshall flume tables. A ga," of 2.6 ft3/s, or about II percent of the headgate inflow, was determined for John Flood Canal from JFHG to JF25 on August 8, 2000 (table 9 and fig. 15). Canal losses and Gains 33 On May 24, 200 I, discharge measurements were made at main channel and diversion locations from JFHG to JF25 (table A6). Leakage was reported at four closed diversion gates (two gates reported as having minor leakage). A gain of 2.7 ft3/s, or about II percent of the headgate inflow, was determined for John Flood Canal from JFHG to JF25 on May 24, 2001 (table 9 and fig. 15). On June 17, 2003, discharge measurements were made at main channel and diversion locations from JFHG to JF25 (fig. 14). Leakage was noted at four closed diversion gates. The total leakage was estimated to be about 0.3 ft3/s. A loss of 2.6 ft3/s, or about 9 percent of the headgate inflow, was determined for John Flood Canal from JFHG to JF25 on June 17,2003 (table 9 and fig. 15). On June 15, 2004, discharge measurements were made at main channel and diversion locations from JFHG to JF25 (fig. 14). Leakage was reported at six closed diversion gates (five gates reported as having only minor leakage), but leakage was measured at only one gate. A loss of 0.2 ft'ls, or about I percent of the headgate inflow, was determined for John Flood Canal from JFHG to JF25 on June 15,2004 (table 9 and fig. 15). Measured losses and gains for John Flood Canal ranged from a gain of 2.7 ft3/s on May 24, 200 I, to a loss of 2.6 ft3/s on June 17,2003. All measurements showed gains in flow between JFHG and JFWG and losses in flow between JFI7 and JF25. Gains ranged from about 0.8 ft3/s (4 percent of the headgate inflow) to about 4.8 ft3/s (20 percent of the headgate inflow) between JFHG and JFWG, and losses ranged from 0.4 ft3/s (3 percent of the subreach inflow) to 5.1 ft3/s (30 per- cent of the subreach inflow) between JFI7 and JF25 (table 9). It is not known why the losses and gains in John Flood Canal are variable. Unlike some of the other canals, losses and gains do not appear to be related to how long the canal was flowing before the measurement. For example, a gain in flow of II percent was measured on August 8, 2000, and on May 24, 2001 (table 9). John Flood Canal had been flowing continuously for about 98 days before the August 8, 2000, measurement but only about 15 days before the May 24, 2001, measurement. The differences in losses and gains probably cannot be explained by changes in flow at the head gate either because flow in the canal was stable (did not vary by more than 6 percent from day to day) in days preceding and follow- ing the measurements. It is possible that diversion gates along the canal could have been recently opened or closed, which might have affected stage in the canal; thus, bank storage may have increased or decreased during the measurement period. Hoehne Canal Hoehne Canal diverts water from the left bank of the Purgatoire River near the city of Hoehne downstream from the Picketwire, Chilili, Enlarged Southside, and Model canal diversions (fig. I). A 4-ft Parshall flume with a free-flow capacity of about 68 ffl,/s is used to measure irrigation diver- sions at the Hoehne Canal headgate.