Category Archives: Bay-Delta

Smelt Extinction and Recovery: The Path Forward

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The March 29, 2016 Delta smelt symposium, part 4 (“Panel Discussion of the Path Forward”) offered some hope but few specific strategies for Bay-Delta smelt recovery.  My own presentation and other presentations earlier in Part 2, focused on how smelt got to the brink of extinction.  In Part 4, the panel of experts was asked to offer ways to bring smelt back from the brink.  Reading the transcript and watching the video of the discussion, there did not appear to be any specific array of actions or coherent strategy offered by the panel.  But on further review, I did find some nuggets that when put together sketch a reasonable course of action.

First, though, it is important to point out that over the past two decades there were two episodes that stopped extinction and brought some (albeit modest and short-lived) recovery with the help of Mother Nature.  The D-1641 water quality standards and the actions required by the Delta Smelt Biological Opinion actions did help.  The symposium should have focused more on those actions that helped, in order to see what further is needed.  Admittedly, the fact that recovery episodes were not more frequent makes this difficult.  It also does not speak well for 20 years of Bay-Delta adaptive management, which in large measure was a test to see how far the Bay-Delta ecosystem could be stressed by taking more and more water without breaking it.  Now that the ecosystem is broken, it is harder to see what helps and what does not.

Here is what I assembled from the panel’s discussion as a reasonable strategy to put the smelt and the Bay-Delta ecosystem back on a recovery course again.

Yolo Bypass – Cache Slough Complex

Simply putting more Sacramento River water down the Bypass might improve the Complex and transfer more of its nutrients, turbidity, and plankton (and smelt) to the north Delta and eastern Bay low salinity zone.  Available water sources include the Colusa Basin Drain and Fremont Weir.  The large Sacramento River agricultural diversions that feed the Drain are minimally used outside the April-October irrigation season.  Present mandates and plans to notch the Fremont Weir would provide a direct source of Sacramento River water to the Bypass.  A long-mandated relocation of the North Bay Aqueduct intake from the Cache Slough Complex to the Sacramento River would also help.

Sacramento Deep Water Ship Channel

Mentioned several times as the last refuge of Delta smelt, the Ship Channel from the Port in West Sacramento to the lower end of Cache Slough offers potential in improving conditions for smelt.  The closed gate at the upper end of the Ship Channel could be opened at key times to pass Sacramento River water into the upper channel to help flush smelt and nutrients into the north Delta, or simply to enhance smelt survival in the channel itself and in the lower Cache Slough Complex.  A panelist suggested dredging the channel.  Opening it in summer would cool the channel and possibly the lower Complex because the opening is near the mouth of the American River with its cool outflow.

Nutrients

The Panel suggested Increasing nutrients, specifically nitrogen, as a means of boosting plankton productivity and smelt survival in the Delta.  Ironically, the Sac Regional Treatment Plant is being forced to reduce its ammonia and nitrogen inputs to the Delta.  But the suggestion holds much promise because plankton blooms and turbidity from them are necessary staples of smelt critical habitat.  A recent spring plankton bloom coincident with a San Joaquin River flow pulse and low Delta exports suggests one option for increasing nutrients and plankton blooms.  Another option is the above-mentioned flow through the Bypass and Ship Channel.  Not exporting higher nutrient low salinity zone water is another.  Employing the Head of Old River Barrier would force more of the high nutrient San Joaquin water into the Central Delta and away from the south Delta export pumps.

More Delta Outflow to the Bay

Almost everyone on the panel suggested the need for more flow to the Bay to help the smelt.  The smelt are simply far better off in wet years.  But no one on the panel suggested upgrading the Delta Outflow requirements in the Bay-Delta D-1641 water quality standards, a process that has been ongoing for nearly a decade.  Relaxation of the outflow requirements in the past four years of drought proved disastrous for smelt, the kind of adaptive management experiment we could do without.  More outflow moves smelt into better habitat in Suisun Bay and Marsh.  It also keeps them away from the export pumps, Delta agricultural diversions, and the warmer lower-turbidity confines of the Delta channels with their profusion of warm water competitors and predators.  A panel member noted the difficulty of “finding” more water for outflow.  The water is there; the need to is export less of it.

Exports

Several panelists suggested there has been too much emphasis on Delta exports, and that we should be focusing more on other solutions like improving habitats.  While physical habitat improvements could help, the fact is that Delta pelagic habitat so essential to smelt and other Delta fishes has been severely degraded by exports (and lower outflows) at an ever increasing rate over the past four decades.  Global warming is further adding to the stress.  None of the panelists mentioned the benefits of export restrictions in the D-1641 standards or biological opinions.  The agricultural community screams to weaken these restrictions, in part from the lack of recognition of their benefits.

Hatchery

Several panelists expressed the opinion that the species is protected from extinction by holding them in captivity in two conservation hatcheries.  While that may be noble, it is not going to save the Delta or smelt.  The option of expansion to production hatcheries was barely discussed, because of an underlying concern of where to put the hatchery fish given the poor existing habitat.  But one panelist suggested stocking may be necessary to provide enough natural spawners to allow them to find one another during the spring spawn.  Regardless, there are times and places where better habitat occurs such that if more smelt were added, it would benefit the population (e.g., when X2 is downstream of the Delta in the fall).

Predators

The panel mentioned predators, but only as one of the negative changes that have occurred over the past several decades.  The panel discussed habitat enhancements as a means of reducing predators or their access to smelt.  There was mention of increasing nutrients to increase phytoplankton food and turbidity, to shade out aquatic plants that shield non-native predator fishes.  This holds promise if export operations do not replace good spatial habitat with incoming warm low turbidity river and reservoir water.  The panel thankfully did not speak of directly removing Delta predators as a solution to the problem, a suggestion fostered by the ag community.

The Solution Package

As a group, the strategies mentioned above offer a reasonable short-term solution package to save the Delta smelt.  Nearly all the actions can be immediately implemented, or at least started.  As a followup to the symposium, I suggest a workshop to develop a plan for such a solution package to guide recovery during the coming years of water battles over the WaterFix (Delta Tunnels), the update of the Bay-Delta Water Quality Control Plan, and the revision of the biological opinions for the long-term operation of the CVP and SWP.

Unprecedented July Experiment – Correction

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In a July 25 post, I wrote of an “unprecedented experiment” that released additional Delta outflow. I wrote that the pulse of Delta outflow in mid-July was in response to the state’s new Delta Smelt Resiliency Strategy July 2016.  Well, while the outcome of increased outflow did indeed create a valuable experiment in regard to smelt, the motivation for the release was simply to allow the water projects to be in compliance with State water quality standards for the Delta.  In this Below Normal water year, the required salinity (EC) at Jersey Point in the west Delta must be maintained below 740 EC on a 14-day average.  As the average EC crept up in mid-July (Figure 1), the water projects increased outflow (by limiting exports) beginning on July 16 (Figure 2).

In a July 14 post, I had recommended 9000 cfs Delta outflow for July to keep smelt and the Low Salinity Zone west of the Delta.  If the projects had in fact maintained July outflow at 9000 cfs, the standard would have been met and the smelt and their habitat would have been better off for it.  A 9000 cfs outflow from July 1-15 would have cost 60,000 AF of water, roughly the cost of the one week of extra water necessary to comply with the standard (the monthly average outflow for July was 8400 cfs).  There was significant daily variation in outflow (Figure 2) that caused significant salt penetration into the Delta (Figure 3) with spring tides (Figure 4).

Perhaps better control of Delta outflow and salt field on a daily basis would benefit Irrigators (the standard is for agriculture) and reduce effects on fish and their habitat.  It also appears that project operators also used more water than was necessary to maintain a consistent 740 EC standard.  The extra water could be credited to the Strategy for helping smelt.

As it turned out, the event did provide an “unprecedented” adaptive management experiment whose effects bear close examination.  If anything, the “experiment” shows that large amounts of water manipulation in the Delta can be accomplished on short notice for whatever purpose.  I regret giving credit to the state and federal water projects for attempting to address the new Delta Smelt Strategy, when no such credit was in fact deserved.  Perhaps in the future the projects will actually seek credit for managing for Delta smelt, if only for that extra increment of water that assures compliance with water quality standards.

igure 1. July 14-day average EC at Jersey Point.

Figure 1. July 14-day average EC at Jersey Point.

Figure 2. Delta outflow (cfs) over past month.

Figure 2. Delta outflow (cfs) over past month.

Figure 3. Daily average Salinity EC at Jersey Point over past month.

Figure 3. Daily average Salinity EC at Jersey Point over past month.

Figure 4. Hourly water level (gage height) at Jersey Point over past month.

Figure 4. Hourly water level (gage height) at Jersey Point over past month.

Delta Update – August 1, 2016

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Just a quick update on Delta fisheries on August 1, 2016. Delta outflow this spring-summer for this below-normal water year was as expected, except for the pulse of up to 14,000 cfs in the July experiment to help Delta Smelt (Figure 1). Year 2000, an above-normal year and a pre-Pelagic Organism Decline year, is shown for comparison.

Figure 1. Delta outflow May-July 2000 and 2016.

Figure 1. Delta outflow May-July 2000 and 2016.

Striped Bass

My earlier optimism for this year’s striped bass production continues to fade.  I continue to believe that the poor success is related to poor early summer Delta outflow based on comparison with year 2000, the last decent year class produced by striped bass in the Bay-Delta as determined by the June Summer Townet Survey.  Figures 2 and 3 show abundance and distribution in 2000 and 2016, respectively.  Densities were an order of magnitude higher in 2000, after spring larvae abundances were similar between the two years.  Figures 4 and 5 show spring-summer salvage at south Delta pumps for 2000 and 2016, respectively.  Again, much higher salvage in 2000 reflects the order of magnitude greater abundance in 2000 than in 2016.

Delta Smelt

Delta Smelt continue to be virtually extinct in the Bay-Delta.  Figures 6 and 7 show abundance and distribution in 2000, the last near normal abundance year (pre-Pelagic Organism Decline), and 2016, respectively.  Figures 8 and 9 show spring-summer salvage at south Delta pumps for 2000 and 2016, respectively.  The relatively high salvage in 2000 reflects the general abundance at the end of the 90’s.  The fact that there are no longer Delta Smelt in the 2016 Townet Survey or in salvage is a very clear indication that Delta Smelt are virtually extinct.  The July experiment, though well intended, was a little too late.

Figure 2. Striped Bass catch per 10,000 cubic meters in June 2000.

Figure 2. Striped Bass catch per 10,000 cubic meters in June 2000.

Figure 3. Striped Bass catch per 10,000 cubic meters in June 2016.

Figure 3. Striped Bass catch per 10,000 cubic meters in June 2016.

Figure 4. South Delta salvage of Striped Bass May-July 2000.

Figure 4. South Delta salvage of Striped Bass May-July 2000.

Figure 5. South Delta salvage of Striped Bass May-July 2016.

Figure 5. South Delta salvage of Striped Bass May-July 2016.

Figure 6. Delta Smelt catch per 10,000 cubic meters in June 2000.

Figure 6. Delta Smelt catch per 10,000 cubic meters in June 2000.

Figure 7. Delta Smelt catch per 10,000 cubic meters in June 2016.

Figure 7. Delta Smelt catch per 10,000 cubic meters in June 2016.

Figure 8. South Delta salvage of Delta Smelt May-July 2000.

Figure 8. South Delta salvage of Delta Smelt May-July 2000.

Figure 9. South Delta salvage of Delta Smelt May-July 2016. (Salvage was zero.)

Figure 9. South Delta salvage of Delta Smelt May-July 2016. (Salvage was zero.)

Experiment – Part 2 Yolo Bypass Flow

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Recently I posted about an unprecedented experiment being undertaken as part of the State’s new Delta Smelt Resiliency Strategy July 2016. That experiment now underway (“Experiment 1”) involves increasing Delta outflow in the latter part of July, 2016. The Strategy also included the North Delta Food Web Adaptive Management Projects (“Experiment 2”), management actions that would benefit juvenile and sub-adult Delta smelt by enhancing the north Delta forage supply for Delta smelt. Experiment 2 involves enhancing flow through the Yolo Bypass to the north Delta by closing the Knights Landing Outfall Gates and routing water from the Sacramento River at Hamilton City (GCID intakes) via the Colusa Basin Drain system into the Yolo Bypass to promote food production in areas where Delta smelt are known to occur. The objective of Experiment 2 is to enhance flow and increase nutrient inputs into the tidal north Delta in the Cache Slough-Lower Bypass region. Future food web enhancement flows would also be considered for “additional months in ways that will not conflict with agricultural and waterfowl management actions based on the availability of water to augment flows in the Yolo Bypass. DWR will also explore options for increasing outflow from the Yolo Bypass during the spring.” Experiment 2 also commenced in July 2016 as an “Emergency Action to Help Delta Smelt”.

As it turned out, the two experiments were timed together, probably to complement one another. Colusa Basin Drain flows increased in mid-July in Experiment 2 via diversion from GCID intakes at Hamilton City (Figure 1). Delta outflow (Figure 2) was increased in Experiment 1 by reducing Delta exports on July 15. Flow through the Yolo Bypass was increased (Figure 3) by closing the Knights Landing Outfall Gates from the Colusa Basin Drain to the Sacramento River and routing the flow through the Knights Landing Ridge Cut to the upper Yolo Bypass on down to Cache Slough and the North Delta (see route in Figure 1). Net flow through lower Cache Slough (Figure 4) increased from the combined effect of the higher flow in Yolo Bypass and the increased flow through Miners Slough and Steamboat Slough that resulted from reduced exports.

So is Experiment 2 having the desired effects? Water temperature in the upper and lower Bypass continue close to the 80°F mark due to high summer air temperatures, although the water temperature in the lower Bypass’s Tule Canal has been measurably higher than that in the adjacent Ship Channel (Figure 5). The higher flow in the Tule Canal likely carries a high organic load as is evident in the low night-time dissolved oxygen levels of 3 to 5 mg/l (Figure 6). Concentrations of salts (Figure 7) and organic matter (Figure 8) increase in the lower Bypass with higher flow. Plankton productivity as measured by chlorophyll levels in the lower Sacramento River channel at Rio Vista immediately below Cache Slough, though low (<10 micro-grams per liter), shows signs of increasing (Figure 9). However, several miles downstream in the channel at Sherman Island, there has been no sign of an increase in plankton (Figure 10). If an increase is indeed real, it is not clear if it is being caused by the higher Delta outflow, lower Delta exports, higher flow in the Bypass, or some combination thereof.

All in all, the warm nutrient- and organic-laden 500-600 cfs of water from the Colusa Basin agricultural drain moving down the Bypass appears to reach the tidal lower Bypass/Cache Slough complex. There, it mixes with higher net and tidal flows of Cache Slough and the Sacramento River. With 80,000 to 100,000 cfs going back and forth during the twice daily tide cycle between Cache Slough and Rio Vista, the Colusa Basin water from the Yolo Bypass is quickly mixed, and its signature is lost. The key question: is there sufficient “fertilizer” and extra plankton in this foreign water to stimulate plankton food production in the lower Yolo Bypass, Cache Slough and the north Delta to benefit Delta smelt? A reduction in river flow at Hamilton City from Experiment 2 might be considered an impact to Sacramento River fish unless additional water is specifically released from Shasta Reservoir for the experiment, or unless GCID water contractors forgo use of a portion of their allocated diversion at Hamilton City.

At a minimum, Experiment 2 has proved the efficacy of an action that might be even more effective from late fall to early spring when water used to stimulate plankton production in the Delta would augment the benefits of cooler, higher flows in the Sacramento River.

Figure 1. Path of flows diverted from the Sacramento River near Hamilton City. Water will move down through GCID's system, into the Colusa Basin Drain and Knights Landing Ridge Cut, through Wallace Weir and the Yolo Bypass, and into the Delta near Rio Vista. Source: http://www.norcalwater.org/wp-content/uploads/Smelt-action-fact-sheet.pdf

Figure 1. Path of flows diverted from the Sacramento River near Hamilton City. Water will move down through GCID’s system, into the Colusa Basin Drain and Knights Landing Ridge Cut, through Wallace Weir and the Yolo Bypass, and into the Delta near Rio Vista. Source: http://www.norcalwater.org/wp-content/uploads/Smelt-action-fact-sheet..pdf

Figure 2. Delta outflow July 2016.

Figure 2. Delta outflow July 2016.

Figure 3. Flow in the upper Yolo Bypass near Woodland July 2016.

Figure 3. Flow in the upper Yolo Bypass near Woodland July 2016.

Figure 4. Net tidally filtered flow in lower Cache Slough July 2016.

Figure 4. Net tidally filtered flow in lower Cache Slough July 2016.

Figure 5. Water temperature at adjacent stations in the lower Bypass Tule Canal (GREEN) and Ship Channel (BLUE) during July 2016.

Figure 5. Water temperature at adjacent stations in the lower Bypass Tule Canal (GREEN) and Ship Channel (BLUE) during July 2016.

Figure 6. Dissolved oxygen level in the Yolo Bypass Tule Canal at Lisbon 19-25 July 2016.

Figure 6. Dissolved oxygen level in the Yolo Bypass Tule Canal at Lisbon 19-25 July 2016.

Figure 7. Specific conductance of water in the lower Yolo Bypass at Liberty Cut late July 2016.

Figure 7. Specific conductance of water in the lower Yolo Bypass at Liberty Cut late July 2016.

Figure 8. Concentration of dissolved organic matter in lower Yolo Bypass at Liberty Cut late July 2016.

Figure 8. Concentration of dissolved organic matter in lower Yolo Bypass at Liberty Cut late July 2016.

Figure 9. Chlorophyll concentrations in the lower Sacramento River in north Delta at Rio Vista 18-28 July 2016.

Figure 9. Chlorophyll concentrations in the lower Sacramento River in north Delta at Rio Vista 18-28 July 2016.

Figure 10. Chlorophyll concentrations in the lower Sacramento River in north Delta at Sherman Island 17-28 July 2016.

Figure 10. Chlorophyll concentrations in the lower Sacramento River in north Delta at Sherman Island 17-28 July 2016.

An Unprecedented Experiment – July 2016

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“State’s Delta smelt plan calls for more water flowing to sea” – This headline to a recent Sacramento Bee article speaks of the state and federal governments’ hope to get more water for Delta outflow to the Bay this summer to help Delta smelt after four devastating drought years.  Smelt are at record lows, and their endangered status under the state and federal endangered species acts requires an effort to help recover them.  When the Delta smelt plan was announced, this year’s Summer Delta Smelt Index had just come in at 0.0, the same as it was last summer.

A grand experiment began on July 15.  With Shasta Reservoir releases held low to save cold water for salmon, more Delta outflow for the experiment was provided by reducing exports from 9000 cfs to 2000 cfs.  Deliveries to South-of-Delta CVP and SWP contractors were cut to a minimum, even though the plan had promised: “[no] cuts to water supply planned.”

Conditions on July 12 can be seen in Figure 1.  Reservoir releases and some natural river flow totaled approximately 30,000 cfs.  Most (80%) of the 20,000 cfs of Delta inflow was coming from Oroville and Folsom reservoirs.  Of that amount, only 7000 cfs was leaving the Delta for the Bay (the required minimum outflow in July of a Below Normal year under state standards is 6500 cfs).  Approximately 6,000 cfs was being diverted from the upper Sacramento River below Redding.  Another 3,000 cfs was being diverted from the lower river and its tribs.  Another 4,000 cfs was diverted in the Delta.  Finally, the state SWP was pumping 7000 cfs and federal CVP was pumping 1000 cfs from the south Delta.

By July 15, conditions in the Delta changed.  Delta outflow doubled, while exports were reduced by 80% (Figure 2).

We often hear about “adaptive management” to test things to see if they help or not.   This is a big, very unprecedented adaptive management experiment.  The purpose is to help Delta smelt recover from a dramatic decline over the past two decades.  However, it will be difficult to help what is not there. There were few smelt out there a month ago; hopefully, there are still enough that the experiment will make a difference.

The important thing now with such an experiment is to make sure we learn everything we can from it.  The following are some questions that should be addressed.

  1. What changes occur in flow, nutrients, salinity and water temperature in the Delta and Bay?
  2. If there are no Delta smelt, what changes occur to the other pelagic organisms such as phytoplankton, zooplankton, shrimp, longfin smelt, striped bass, herring, anchovy, and threadfin shad?
  3. Will the change stimulate a plankton bloom that benefits the Bay-Delta estuary?

From the point of view of managing the experiment, it is good that other important factors such as Delta inflow remain unchanged, so that there are not too many variables to filter out as determinative in any response.  It will be difficult enough to determine the relative importance of higher outflow versus lower export.

Hydrology

Preliminary results indicate that the experiment (as expected) had a noticeable effect on Delta hydrology.  By July 24, outflow had dropped back from its peak during the experiment of 14,000 cfs to 9000 cfs (Figure 3), as exports were again increased to about 7000 cfs, as shown in Old and Middle River tidally averaged flow (Figure 4).  Net lower San Joaquin River flow at Jersey Point initially increased sharply in response to the reduced exports (Figure 5).  The net flows diverted from the lower Sacramento to the lower San Joaquin via Threemile Slough were also reduced (Figure 6).

Salinity

Salinity (EC) eventually responded to the higher outflows as the pulse of freshwater pushed westward.  Salinity on the lower Sacramento at Emmaton (Figure 7) and Jersey Point on the lower San Joaquin (Figure 8) declined measurably.  Salinity also declined downstream at the confluence of the two rivers near Collinsville in eastern Suisun Bay (Figure 9).

Water Temperature

There has been slightly lower water temperature in the western Delta.  This is at least partially explained by cooler air temperatures during the experiment.  The water temperature at X2 (location of 2 ppt salinity or 2700 EC declined as X2 was located on-average further west during the experiment  (Figure 10).  However, that too could be explained by lower air temperatures.

Plankton Blooms

So far there is no evidence of enhanced plankton production by the experiment.  There has been little change in chlorophyll measured at selected gaging stations in the central and west Delta.

Fish

While results of Delta-wide fish surveys will not be available for some time, results of export salvage of two pelagic Delta species, striped bass and threadfin shad, showed sharp reductions as expected (Figures 11 and 12).

Figure 1. Water conditions in mid July 2016 in the Sacramento Valley and Delta before the experiment. Red denotes major water releases in cfs from the Valley’s four largest reservoirs. Blue denotes three key river flow locations: lower Sacramento River upstream of the Feather River, Freeport coming into the Delta, and Delta outflow. Green denotes south Delta exports.

Figure 1. Water conditions in mid July 2016 in the Sacramento Valley and Delta before the experiment. Red denotes major water releases in cfs from the Valley’s four largest reservoirs. Blue denotes three key river flow locations: lower Sacramento River upstream of the Feather River, Freeport coming into the Delta, and Delta outflow. Green denotes south Delta exports.

Figure 2. Flow conditions in the Sacramento Valley and Delta on 20 July 2016. Delta outflow is 14,000 cfs. Sacramento River flow above the mouth of the Feather River was 4,000 cfs. Sacramento River inflow to the Delta at Freeport is 19,000 cfs. (Note total Delta inflow was about 20,000 cfs. Total Central Valley reservoir releases and uncontrolled river inflows was over 30,000 cfs.). About two-thirds of the Delta inflow came from Feather Riverand American River reservoirs. Though only 2000 cfs was being exported from the south Delta projects, approximately 14,000 cfs of Sacramento Valley reservoir releases were being diverted for water supply from Sacramento Valley rivers and the interior Delta. Nearly all San Joaquin Valley reservoir releases were being diverted.

Figure 2. Flow conditions in the Sacramento Valley and Delta on 20 July 2016. Delta outflow is 14,000 cfs. Sacramento River flow above the mouth of the Feather River was 4,000 cfs. Sacramento River inflow to the Delta at Freeport is 19,000 cfs. (Note total Delta inflow was about 20,000 cfs. Total Central Valley reservoir releases and uncontrolled river inflows was over 30,000 cfs.). About two-thirds of the Delta inflow came from Feather Riverand American River reservoirs. Though only 2000 cfs was being exported from the south Delta projects, approximately 14,000 cfs of Sacramento Valley reservoir releases were being diverted for water supply from Sacramento Valley rivers and the interior Delta. Nearly all San Joaquin Valley reservoir releases were being diverted.

Figure 3. Delta outflow increased to 14,000 cfs during the July 15-23 experiment.

Figure 3. Delta outflow increased to 14,000 cfs during the July 15-23 experiment.

Figure 4. The tidally filter flow in the central Delta showed about a 6500 cfs reduction in the flow in Old and Middle River toward the south Delta export pumps.

Figure 4. The tidally filter flow in the central Delta showed about a 6500 cfs reduction in the flow in Old and Middle River toward the south Delta export pumps.

Figure 5. The experiment brought a sharp response in the tidally filtered flow at Jersey Point in the lower San Joaquin River in the western Delta.

Figure 5. The experiment brought a sharp response in the tidally filtered flow at Jersey Point in the lower San Joaquin River in the western Delta.

Figure 6. The experiment brought a reduction in net flows pulled from the lower Sacramento River to the lower San Joaquin via Threemile Slough.

Figure 6. The experiment brought a reduction in net flows pulled from the lower Sacramento River to the lower San Joaquin via Threemile Slough.

Figure 7. Salinity (EC) at Emmaton on the lower Sacramento River just north of Antioch 14-24 July, 2016.

Figure 7. Salinity (EC) at Emmaton on the lower Sacramento River just north of Antioch 14-24 July, 2016.

Figure 8. Salinity (EC) at Jersey Point on the lower San Joaquin River near Antioch 14-24 July, 2016.

Figure 8. Salinity (EC) at Jersey Point on the lower San Joaquin River near Antioch 14-24 July, 2016.

Figure 9. Salinity (EC) at Collinsville near the confluence of the lower Sacramento and San Joaquin channels in eastern Suisun Bay 14-24 July, 2016.

Figure 9. Salinity (EC) at Collinsville near the confluence of the lower Sacramento and San Joaquin channels in eastern Suisun Bay 14-24 July, 2016.

Figure 10. Water temperature (F) at Collinsville in eastern Suisun Bay 14-24 July, 2016. Red dots indicate water temperature when X2 was located at Collinsville

Figure 10. Water temperature (F) at Collinsville in eastern Suisun Bay 14-24 July, 2016. Red dots indicate water temperature when X2 was located at Collinsville

Figure 11. Salvage of striped bass at south Delta export facilities July 1-20, 2016.

Figure 11. Salvage of striped bass at south Delta export facilities July 1-20, 2016.

Figure 12. Salvage of threadfin shad at south Delta export facilities July 1-20, 2016.

Figure 12. Salvage of threadfin shad at south Delta export facilities July 1-20, 2016.