Hypolimnetic oxygenation 2: oxygen dynamics in a large reservoir with submerged down-flow contact oxygenation (Speece cone)

Figures & data

Table 1. Morphometric parameters for Camanche Reservoir, California at full pool

Parameters	Metric units	English units
Maximum volume, V—full (typical summer)	514 million m^3 (353)	417,000 acre-feet (287,000)
Length, L	9.5 km	6 miles
Width at dam, b	4.8 km	3 miles
Reservoir area, Ar—full (typical summer)	31 km^2 (25.7)	12 square miles (9.9)
Catchment area Ac	1,500 km^2	577 square miles
Ratio Ac:Ar	48	48
Predicted trophic state based on Ac:Ar	Mesotrophic	Mesotrophic
Maximum depth, zmax full (typical)	41 m (34.6)	135 ft (120)
Mean depth, ž full (typical)	17 m (36.4)	56 ft (45)
Mean inflow	911 million m^3	741,000 acre-feet
Hydraulic residence time, HRT	∼1.8 yr	∼1.8 yr
Elevation, full amsl	73 m	220 ft
Height of dam	52 m	171 ft
Year constructed	1964	1964

Figure 1. Sketch of the Speece cone and ancillary devices installed at Camanche Reservoir (from Brown and Caldwell 1995).

Figure 2. (a) Photograph of Speece cone assembly using a raft near the dam in June 1993. The white cone and green ancillary piping are shown, including T-shaped intake. The water pump is being lowered into the vertical piping. Several workers show scale. (b) Shoreline facilities; ∼10 m high evaporator and 50 m³ liquid oxygen tank; automobile shows scale.

Figure 3. Map of station locations. Multiple repetitive synoptic sampling stations (X), longitudinal stations (numbers 1–5, dam index station is number 1) and Speece cone (Δ) in Camanche Reservoir. Line indicates approximate boundary of thalweg, representing deeper water (>18 m).

Figure 4. Initial effect of the HOS on deeper water layer. HOS started in partial operation on 23 July 1993 and was in full operation by the 28 July. Squares and gray dotted line correspond to 14 July 1993 before oxygenation; circles and full line represent 28 July 1993 after oxygenation.

Figure 5. (a) Temperature and (b) dissolved oxygen depth profiles at similar times of year before HOS showing anoxia throughout the hypolimnion before HOS (26 Aug 1992, squares, short dashed line), initial results after about 5 weeks of HOS (3 Sep 1993, triangles, long dashed line) and a profile 21 yr later (17 Sep 2014, circles, gray full line) using about one-third of the oxygen initially added. HOS had little effect on the thermocline, which begins at 6 to 7 m.

Figure 6. Dissolved oxygen (DO) and temperature at the bottom near the Speece cone during off/on tests in 1993–1994. (a) In 1993 DO rose rapidly and remained constant after HOS was switched on in July 1993. Temperature rose slightly. (b) In 1994 when HOS was switched off DO fell rapidly while temperature rise ceased.

Table 2. Short-term variations in dissolved oxygen and temperature (Temp) for the bottom water (0.5 m above sediments) near the Speece cone for the first few days before and after the HOS was started on 23 July 1993. Also shown is the effect of turning the HOS off in mid-season (2 Sep 1994)

1993	DO, mg/L	Temp, C	1994	DO, mg/L	Temp, C
5 Jul	5.5	11.5	23 Aug	6.0	13.7
8 Jul	5.2	11.7	24 Aug	5.5	13.7
10 Jul	5.0	11.5	25 Aug	5.0	13.6
13 Jul	5.0	11.7	26 Aug	5.5	13.7
15 Jul	4.8	11.8	27 Aug	6.3	13.7
18 Jul	4.2	11.9	28 Aug	5.0	13.6
20 Jul	4.0	12.0	29 Aug	5.0	13.7
23 Jul a.m.	HOS partial start		30 Aug	6.1	13.7
23 Jul	3.5	12.0	31 Aug	5.2	13.7
25 Jul	5.8	12.6	1 Sep	5.7	13.8
28 Jul	HOS full operation		2 Sep	5.9	13.8
28 Jul	6.0	12.8	2 Sep	HOS shut down
30 Jul	5.8	12.8	3 Sep	4.9	13.8
2 Aug	5.5	13.0	4 Sep	4.6	13.8
4 Aug	5.3	13.1	5 Sep	4.5	13.8
7 Aug	6.0	13.2	6 Sep	4.0	13.8
9 Aug	5.8	13.4	7 Sep	4.0	13.8
12 Aug	6.2	13.5	8 Sep	3.8	13.8
			9 Sep	3.7	13.7
			14 Sep	3.0	13.6

Figure 7. Spatial extent of oxygenation plume during HOS on/off testing in 1994. Most water volume is contained in the first 5 km of the reservoir. (a) Oxygenation shut down for 24 d; most hypolimnion deep water is red (anoxic), and small area of DO ∼1 mg/L near bottom near dam and Speece cone is the remnant of earlier HOS operation. (b) After 29 d of oxygenation. The oxygenated plume (orange yellow >5 mg/L) extended 4.5 km upstream.

Figure 8. Moving surface, whole-year depth–time isopleths of dissolved oxygen in 2004, 11 yr after HOS installation with less oxygen used. Note: Colors here are reversed relative to Figure 7; here blue = low DO and red high DO. The bottom water DO was maintained at >2 mg/L and the mid-upper hypolimnion is almost anoxic in the fall since fish can pass through or around this potential barrier (Horne et al. 2019a).

Table 3. Oxidation–reduction potential (ORP in mV) depth profiles at sites near and far from the Speece cone in 1994 (see Fig. 3). Values in bold = hydrogen sulfide odor smelled by field crew in bottom water samples

Depth above bottom	Site 1 (HOS site)	Site 2 (3.7 km)	Site 3 (5.3 km)	Site 4 (7.3 km)	Site 5 (11 km)
12 Aug 1994 following 24 d of no oxygen					17 Aug
4 m	394	389	414	380	501
3 m	393	386	311	380	501
2 m	371	341	264	346	499
1 m	315	339	250	268	492
14 Sep 1994 after 33 d of oxygenation
4 m	394	421	79	50	358
3 m	395	422	71	32	355
2 m	396	421	61	24	352
1 m	396	420	54	18	350
5 Oct 1994 after 54 d of oxygenation
4 m	329	279	355	397	405
3 m	334	300	357	390	388
2 m	336	304	358	385	384
1 m	337	296	353	374	383

Brown & Caldwell Inc. 1995. Camanche Reservoir oxygenation demonstration system: report on operation 1993/94. Oakland (CA): Brown & Caldwell, Alex Horne Associates & Biosystems Analysis Inc. for EBMUD.

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Horne AJ. 2019a. Hypolimnetic oxygenation 1: win-win solution for massive salmon mortalities in a reservoir tailwater hatchery on the Mokelumne River, California. Lake Reserve Manage. 35(3):308–322. doi:10.1080/10402381.2019.1649770.

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