Delta
Sisyphus of the Slough: The Uphill Battle of Removing Invasive Aquatic Vegetation
Before the turn of the 21st century, the Sacramento-San Joaquin River Delta was dubbed one of the most biologically invaded estuaries in the world, with non-native plants at the root of the issue. Over 25 years later, the battle against invasive aquatic vegetation in the Delta continues at an even accelerated rate, despite innovative management efforts. Read More…
The Delta Divide: Bass Trends In Salmon Migration Corridors
Recent research has established that very few juvenile Chinook salmon (Oncorhynchus tshawytscha) survive the migration from their birthplace in California’s Central Valley tributaries, through the Sacramento-San Joaquin Delta, and out to the Pacific Ocean. Records from rotary screw traps on the Stanislaus and Tuolumne rivers show that most young salmon do not even make it as far as the San Joaquin River, still hundreds of miles away from the Golden Gate Bridge. Numerous elements contribute to the low survival of juvenile salmonids, including habitat alteration, pesticide pollution, and predation by non-native fish. Most ongoing restoration efforts attempt to lessen the Read More…
Science Symposium Examines Factors Affecting Salmon Survival in the South Delta
A recent science symposium hosted by the State Water Contractors, a non-profit association of 27 public agencies in California, brought people together from across the scientific community to examine the science behind spring flows and water export limits in the south Sacramento-San Joaquin Delta. The symposium, titled Spring-Season San Joaquin River Flows and South Delta Exports, sought to understand why most Central Valley salmon populations continue to decline despite more than 30 years of water management actions intended to protect the species. Presentations and discussions focused on the history of flow and water export regulations intended to improve juvenile salmon Read More…
Droughts and Floods — Flashback Friday
In today’s Flashback Friday, we discuss California’s climate change conundrum, droughts and floods. It’s almost an understatement to call California’s Sacramento-San Joaquin Delta “complex.” This highly altered ecosystem supports one of the most complicated water-management systems in the world. California also experiences the most variable precipitation regime in the country, with wide swings between drought and downpours. Wildly varying rates of precipitation, increasing infrastructure construction, and changing water demands all present challenges to effectively managing water and conserving the Delta ecosystem. Now the emergence of climate change among the list of stressors guarantees the Delta of tomorrow will not be the same as Read More…
Salmon Migration Struggle — Flashback Friday
In today’s Flashback Friday, we examine the plethora of struggles Chinook salmon face when migrating to and from the San Joaquin River in California’s Central Valley. Much like old-timer tales of walking to school uphill both ways, it can seem like Chinook salmon in the Central Valley have to swim uphill both ways when migrating to and from the ocean. It’s no secret that young salmon and steelhead face a formidable obstacle course when trying to exit the Sacramento-San Joaquin River Delta toward the Pacific Ocean. A maze of natural and man-made stream channels, dead-end sloughs, predators, rip-rap-lined channels cut off from Read More…
The Salmon Struggle for Survival out of the San Joaquin River
Much like old-timer tales of walking to school uphill both ways, it can seem like Chinook salmon in the Central Valley have to swim uphill both ways when migrating to and from the ocean. It’s no secret that young salmon and steelhead face a formidable obstacle course when trying to exit the Sacramento-San Joaquin River Delta toward the Pacific Ocean. A maze of natural and man-made stream channels, dead-end sloughs, predators, rip-rap-lined channels cut off from floodplains, and pumps that reverse the flow of rivers all confuse, consume, and strand juvenile salmon. Researchers and managers have long known survival is Read More…