{"id":1690,"date":"2017-06-26T19:51:24","date_gmt":"2017-06-27T02:51:24","guid":{"rendered":"http:\/\/calsport.org\/fisheriesblog\/?p=1690"},"modified":"2017-06-26T19:51:24","modified_gmt":"2017-06-27T02:51:24","slug":"delta-status-end-of-june-2017","status":"publish","type":"post","link":"https:\/\/calsport.org\/fisheriesblog\/?p=1690","title":{"rendered":"Delta Status End of June 2017"},"content":{"rendered":"

Despite the fact that it is a record wet year with abundant spring snowmelt, early summer conditions in the Delta in 2017 are not looking good.\u00a0 Rapidly falling Delta inflows and a late June heat wave have led to salt water intrusion and extremely warm water temperatures detrimental to salmon and smelt throughout the Delta.<\/p>\n

Notably, lower Sacramento River flows at Wilkins Slough upstream of the mouth of the Feather River are down about a third compared to the last Wet year, 2011 (Figure 1).\u00a0 Flow is only about 7000 cfs and water temperatures are 73-75\u00b0F, well above the water quality standard of 68\u00b0F.\u00a0 Winter-run and spring-run adult salmon will not move up the river at these temperatures.\u00a0 Why is flow so low?\u00a0 Good question.\u00a0 Shasta is nearly full but releases are down about a third for a wet year at 8000 cfs.\u00a0 In contrast, the San Joaquin River flow coming into the Delta near Stockton is 13,000-15,000 cfs, with water temperatures of 71-73\u00b0F.<\/p>\n

Feather River flow contributions to the Sacramento River are very low (Figure 2).\u00a0 Yuba and American River flow contributions remain strong at about 4000 cfs each.<\/p>\n

Overall Delta outflow in late spring 2017 is lower than Wet year 2011 (Figure 3).\u00a0 Delta inflow is approximately 34,000 cfs, with about equal contribution from the Sacramento and San Joaquin rivers. Delta exports have been maximum through June at 11,400 cfs.\u00a0 With in-Delta use taken into account, Delta outflow is estimated at 19,000-21,000 cfs. (Note: USGS measured outflow about 14,000 cfs with tides taken into account on June 22.)<\/p>\n

With sharply falling Delta inflow and outflow, high exports, and the heat wave, the Delta is unusually warm at 72-75\u00b0F. Such temperatures are detrimental to juvenile smelt, salmon, and sturgeon survival.\u00a0 Juvenile salmon have been present in the Delta well into June on their seaward migrations (Figure 4).<\/p>\n

\u00a0<\/sup>With falling Delta inflow and high exports, the Delta is stagnating and salt water is intruding at the west end at Chipps Island (Figure 5).\u00a0 The Low Salinity Zone with the few Longfin and Delta smelt that are left is moving into the Delta on incoming tides.\u00a0 The water temperature at the head of the LSZ is already 72\u00b0F (Figure 6).\u00a0 Higher temperatures would be very detrimental to surviving smelt and seaward-moving juvenile salmon.\u00a0 The further east the LSZ moves, the warmer it usually becomes.<\/p>\n

There is a consistent late spring pattern in the operation of State Water Project and Central Valley Water Project in which they cut reservoir releases while exporting the remnant freshwater pool in the Delta. \u00a0Even in this very wet year we are again witnessing this water supply control strategy.\u00a0 The problem is the rivers get too warm even to the point of violating water quality standards.\u00a0 With less water and warmer water entering the Delta, the Delta also becomes too warm.\u00a0 Delta water quality standards and endangered species permits are supposed to keep this from happening.\u00a0 Come July 1, conditions will only get worse, especially as snowmelt declines and San Joaquin flows drop sharply.<\/p>\n

What can be done?\u00a0 Both Shasta and Oroville reservoir releases are lower than normal.\u00a0 Just keeping their cold-water releases near normal and allowing the flows to pass through the Delta would nearly fix the problem.\u00a0 Exports in the 1970\u2019s and 1980\u2019s were limited to 6000-9000 cfs in June-July of Wet years.\u00a0 Reducing the present export level of 11,000 cfs would also help.\u00a0 These would be very reasonable actions given present water supplies in the Central Valley.<\/p>\n

\"\"<\/a>

Figure 1. Flow in the lower Sacramento River at Wilkins Slough in late spring of 2011 and 2017.<\/p><\/div>\n

\"\"<\/a>

Figure 2. Lower Feather River flow at Gridley upstream of the mouth of the Yuba River.<\/p><\/div>\n

\"\"<\/a>

Figure 3. Delta outflow in late spring 2011 and 2017.<\/p><\/div>\n

 <\/p>\n

\"\"<\/a>

Figure 4. Salmon salvage at Delta fish facilities in June 2017. Source: https:\/\/www.wildlife.ca.gov\/Conservation\/Delta\/Salvage-Monitoring<\/a><\/p><\/div>\n

\"\"<\/a>

Figure 5. Salinity (EC) at Mallard Island gage near Chipps Island (eastern end of Suisun Bay) in June 2017.<\/p><\/div>\n

\"\"<\/a>

Figure 6. Water temperature at Mallard Island gage near Chipps Island (eastern end of Suisun Bay) in June 2017.<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

Despite the fact that it is a record wet year with abundant spring snowmelt, early summer conditions in the Delta in 2017 are not looking good.\u00a0 Rapidly falling Delta inflows and a late June heat wave have led to salt … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[15,6,12],"tags":[],"class_list":["post-1690","post","type-post","status-publish","format-standard","hentry","category-bay-delta","category-smelt","category-water-quality"],"jetpack_featured_media_url":"","jetpack-related-posts":[],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts\/1690","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1690"}],"version-history":[{"count":4,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts\/1690\/revisions"}],"predecessor-version":[{"id":1702,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts\/1690\/revisions\/1702"}],"wp:attachment":[{"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1690"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1690"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1690"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}