- Author: John Madsen
- Posted by: Guy B Kyser
We were sampling plots in the Delta in July 2016, and found a small clump of this plant – pickerelweed (Pontederia cordata). Generally considered a desirable native wetland plant, it happens to fall in the same botanical family as the baddest of the bad in the Delta – waterhyacinth (Eichhornia crassipes). What does family mean in the botanical world, anyway? Although native here, pickerelweed is at best considered “occasional” in the Delta. Waterhyacinth falls somewhere between “abundant” and a “scourge,” depending on the year of reference. While there are a number of similarities in appearance (particularly in the characteristics of the flower, which is the original...
- Author: John Miskella
- Posted by: Guy B Kyser
Waterhyacinth (Eichhornia crassipes) is a floating perennial species that has become a serious management issue as it invades aquatic ecosystems around the world. In the Sacramento-San Joaquin Delta in California, the species forms large, dense mats on the water surface that inhibit boating, fishing, water access, and decrease light availability below the floating mat.
While the leaves of waterhyacinth generally turn brown and die during the winter, many waterhyacinth plants survive the winter and grow new leaves in the spring. Warmer spring temperatures also cause the plants to grow stolons, or spreading stems, from which daughter plants grow (Figure 1). Stolon growth is a key driver of waterhyacinth...
- Author: Karen Jetter
- Author: Kjersti Nes
- Posted by: Guy B Kyser
The U.S. Bureau of Reclamation (BOR) is one of the agencies responsible for operating a facility that pumps water from the Sacramento-San Joaquin Delta into the California Aqueduct. The California Aqueduct pumps water for uses south of the facilities. This water is used for agriculture in the San Joaquin Valley valued at $33.4 billon in 2015 (CAC 2015), and for millions of other users in Californian homes and businesses.
Before that water can be pumped, debris, weeds and fish must be removed. This is done at the Tracy Fish Facility. A series of screens and diversions are used to remove the objects and capture the fish. The debris is mechanically removed from the river, and the fish are transported and released...
- Author: Dr. Patrick Moran
- Posted by: Guy B Kyser
Biological control of water hyacinth in the Delta is being developed as part of an integrated, adaptive management plan for sustainable, long-term control of water hyacinth. Water hyacinth is one of the most troublesome floating aquatic weeds in the Delta, and one of the key targeted species in the USDA-ARS-funded Delta Region Areawide Aquatic Weed Project (DRAAWP). Biological control can greatly assist the weed control program managed by the Division of Boating and Waterways-California Department of Parks and Recreation (DBW). Before biocontrol can be fully implemented, the control plan must be reviewed by the U.S. Fish and Wildlife Service (USFWS) and the NOAA-National Marine Fisheries Service. USFWS is responsible for protecting...
- Author: Sharon Lawler
- Author: Maribel Portilla
- Posted by: Guy B Kyser
Mosquito research by Maribel Portilla and Sharon Lawler recently included an experiment on how Egeria, or Brazilian water weed, affects mosquito populations. Egeria is a submersed aquatic weed that can cause problems in channels and irrigation waterways. Mosquitoes also breed in stagnant waters, but, we asked, is this because of the weeds?
We used large cattle-watering tanks to simulate stagnant, back-water areas with and without infestations of Egeria (Figure 1). Five tanks had no weeds, five had healthy Egeria, and five had Egeria that was sprayed with the herbicide fluridone. We added zooplankton and insects colonized naturally.
Interestingly, there were fewer...