State Board: Increase Sacramento River Flow

Posted on July 5, 2016 by Tom Cannon

The State Water Resources Control Board is responsible for enforcing water rights and the Sacramento River Basin Plan that protects beneficial uses including fish and water quality.¹ The Basin Plan’s 68°F objective for the lower Sacramento River is clearly being violated right now because of low Sacramento River flows brought about by lower than normal Shasta releases and a 100 % allocation of water to Sacramento Valley water contractors. The State Board has jurisdiction over both of these factors through control of water rights. The State Board is about to review Reclamation’s Water Temperature Plan (WTP) for summer 2016, which calls for a 10,500 cfs release in July, several thousand cfs below normal, to conserve Shasta’s cold-water pool for salmon through the summer and fall. The WTP however has no provisions for cutting downstream water use. Thus, flows in the lower Sacramento River will be lower, with higher water temperatures that violate the Basin Plan. The flows must be raised at Wilkins Slough (RM 125) by either increasing Shasta releases or reducing water diversions, or a combination thereof.

The Basin Plan objective of 68°F is there to protect salmon and sturgeon migrating and rearing in the lower Sacramento River. Water temperatures above 68°F are stressful to the fish, affecting growth, survival, and subsequent reproduction. Present water temperatures in the lower river (Figure 1), caused in part by low flow (Figure 2), are lethal to salmon and sturgeon. In 2010 and 2012, water years similar to 2016, flows were higher and water temperatures were lower in early summer (Figures 3-6).

The State Board, in reviewing the WTP, must explicitly consider flows and water temperatures in the lower Sacramento River under its broader responsibilities to protect fish as prescribed in the Basin Plan and in various water rights orders.

Figure 1. Water temperature of lower Sacramento River at Wilkins Slough (RM 125) in early summer 2016.

Figure 2. Sacramento River flow at Wilkins Slough (RM 125) in early summer 2016.

Figure 3. Water temperature of lower Sacramento River at Wilkins Slough (RM 125) in early summer 2010.

Figure 4. Sacramento River flow at Wilkins Slough (RM 125) in early summer 2010.

Figure 5. Water temperature of lower Sacramento River at Wilkins Slough (RM 125) in early summer 2012.

Figure 6. Sacramento River flow at Wilkins Slough (RM 125) in early summer 2012.

http://www.waterboards.ca.gov/waterrights/ board_decisions/adopted_orders/orders/1990/wro90-05.pdf ↩

June Protection Lost for Delta Smelt

Posted on July 4, 2016 by Tom Cannon

In a May post and again in an early June post, I offered some hope for Delta smelt. But the Smelt Biological Opinion and the Smelt Working Group failed the smelt once again. The only protection afforded Delta smelt in June is the -5000 cfs Old-Middle River negative flow limit, which has the practical effect of limiting Delta exports to about 5000-6000 cfs. Historically (from 1978-1994), D-1485 water quality standards limited June exports to 6000 cfs in order to protect Delta fish, but there are no June export limits in the existing D-1641 standards.

The last Smelt Working Group meeting was May 31. The only biological opinion criterion left to manage, the -5000 cfs OMR limit, was gone because of a little known trigger in the opinion that dropped the OMR limit when the water temperature in the South Delta first reaches 25°C or 77°F (Figure 1). The reasoning behind this trigger in the biological opinion was that exports would no longer hurt smelt because 25°C/77°F water temperatures would kill them anyway. The problem with this logic is that exports can still pull smelt from their cooler nursery in the west and north Delta (Figures 2 and 3) into warm water killing zone in the central and south Delta. Fortunately, export pumping in June 2016 was limited (Figure 4) by Reclamation’s holding back Shasta Reservoir storage releases to conserve cold-water for salmon. Otherwise June exports and negative OMR flow would likely have been higher.

Reclamation has begun consulting with fishery agencies on a new biological opinion. We can only hope that they improve protections for smelt and other Delta fish in spring and summer. I suggest strong OMR restrictions any time the Delta Cross Channel in the far north Delta is closed, as this will help minimize (1) the draw of smelt from their nursery area and (2) the degradation of the Low Salinity Zone by south Delta exports.

Figure 1. Water temperature in Clifton Court Forebay in the South Delta in June 2016.

Figure 2. Water temperature at Jersey Point in the west Delta in June 2016.

Figure 3. Water temperature in the lower San Joaquin River at Three Mile Slough in June 2016.

Figure 4. June OMR flow. The Smelt Biological Opinion limit is for June is -5000 cfs, but that provision does not apply once south Delta water temperature reaches 25°C/77°F.

Salmon Season Opens July 16

Posted on July 2, 2016 by Tom Cannon

The Sacramento River salmon season opens on July 16 in the lower Sacramento River below Red Bluff, and in the lower Feather and American Rivers, as well as in the Bay-Delta. Will the Sacramento River remain cold enough to allow the fall-run salmon to leave the Bay and Delta for the rivers? Are the lower rivers warming into the 72-75°F range that blocks migration and stresses the adult salmon?

Salmon will be headed for the upper river reaches where water temperatures are cool, near 60°F. The Bay and west Delta remain below 70°F. At Rio Vista and Freeport on the Sacramento River in the north Delta water temperature have reached 70°F and are slowly rising. Upstream of the Delta, downstream of the points of relatively cool inflow from the Feather and American rivers, the Sacramento River remains just below 70°F.

Upstream from the mouth of the Feather, water temperatures in the Sacramento River are increasingly problematic. The hundred miles of river upstream from the mouth of the Feather to Hamilton City (RM 200) have a Central Valley Basin Plan upper temperature limit of 68°F in summer to protect the salmon during their run up the river in summer and fall. The only water temperature recorder is at Wilkins Slough, about mid-way in the reach, about 20 miles below Colusa (RM 143). Water temperature at Wilkins Slough has risen from 65°F to 72°F in the past week.

Summer water temperatures at Wilkins Slough vary with air temperatures, but are also determined in part by river flow. In the critically dry year last summer, water temperatures in July approached the lethal level for salmon of 80°F (Figure 1) under very low river flows (Figure 2). In below-normal year 2010, water temperatures were cooler (Figure 3) under higher river flows (Figure 4).

The flow at Wilkins Slough has increased over the past week from 3500 cfs to 5000 cfs, but the water temperature has continued to rise to 72°F with higher air temperatures. With even warmer air temperatures forecasted in the coming weeks, river flow should be increased to 6000 cfs or higher as in 2010 to maintain water temperature below 72°F. Temperatures above this level impede migration and stress adult salmon. A flow of 8000 cfs, as occurred in the summer of dry year 2012, would be more protective (Figures 5 and 6).