Flow routing with bottom withdrawal to improve water quality in Walnut Canyon Reservoir, California

Figures & data

Table 1 Basin characteristics of Walnut Canyon Reservoir.

Latitude	33°50′32^″N
Longitude	117º44′59^″W
Crest Elevation (m)	257.0
Surface Area (m^2)	2.0×10^5
Maximum Volume (m^3)	3.7×10^6
Mean Depth (m)	18.5
Maximum Depth (m)	31.5

Figure 1 Study site: Walnut Canyon Reservoir, near Anaheim, CA.

Table 2 Physical conditions present on calibration sampling dates.

Date (2010)	Uwiind (m s^−1)	S (J m^−2)	TKEwind (W m^−2)	TKEinflow (W m^−2)
April 29	1.95	112	3.33×10^−6	3.1×10^−5
June 14	1.60	319	1.83×10^−6	3.1×10^−5
July 22	1.77	533	2.51×10^−6	3.1×10^−5

Figure 2 Observed (symbols) and predicted (line) (a) lake surface elevation and (b) temperature profiles over time.

Figure 3 Observed (symbols) and predicted (line) (a) dissolved oxygen (DO) profiles and (b) total phosphorus concentrations over time. Deviation between predicted and observed metalimnetic DO attributed to chlorinated inflows and induced oxygen demand.

Figure 4 Predicted temperature profiles in water column over time: (a) existing (reference), (b) aeration, (c) hypolimnetic oxygenation, and (d) flow routing+bottom withdrawal.

Figure 5 Predicted DO profiles in water column over time: (a) existing (reference), (b) aeration, (c) hypolimnetic oxygenation, and (d) flow routing+bottom withdrawal.

Figure 6 Predicted total P profiles in water column over time: (a) existing (reference), (b) aeration, (c) hypolimnetic oxygenation, and (d) flow routing+bottom withdrawal. Note difference in scale for existing 2010 conditions (0–1.6 mg/L) vs. other scenarios (0–0.16 mg/L).

Figure 7 Observed (a) temperature and (b) DO profiles over time in Walnut Canyon Reservoir, with flow routing with bottom withdrawal implemented in 2011.

Figure 8 Observed concentrations of (a) sulfide, (b) total Mn, and (c) total P.

Figure 9 Thermal stability of the water column of Water Canyon Reservoir from measured temperature profiles with offline storage and operation of a SolarBee in 2010 and flow routing/bottom withdrawal in 2011.