Time filter

Source Type

Santa Rosa, CA, United States

Horton G.E.,U.S. Geological Survey | Letcher B.H.,U.S. Geological Survey | Kendall W.L.,Sonoma County Water Agency
Transactions of the American Fisheries Society | Year: 2011

Robust estimates of survival and movement are important for informing the recovery of fish populations as well as for the study of life history, behavior, and population ecology. We present a multistate capture-recapture model that allows separate and simultaneous estimation of true survival and fidelity to the study reach in the presence of imperfect recapture and detection probabilities. The key study design element that permitted this separation was the use of a multiple-antenna array to detect passive integrated transponder (PIT) tagged individuals as they emigrated from the study area. The modeling approach incorporated live recapture data during discrete sampling occasions with observational data on antenna detections of tagged individuals as they exited the study area between sampling occasions. The multistate emigration model was applied to empirical data from a stream-dwelling, PIT-tagged cohort of Atlantic salmon Salmo salar for which emigration was continuously monitored by using a pair of stationary PIT tag antennas. The study design we outline presents a way to inform key management, recovery, and ecological questions. Our analysis showed how estimates of the joint probability of surviving and remaining faithful to the study reach (apparent survival) that were based solely on live recapture data (e.g., fromthe Cormack-Jolly-Seber model) masked the patterns that were revealed when true survival and emigration were separately estimated with the multistate emigration model. Use of the multistate model also allowed us to consider size dependence in survival and emigration in a straightforward way; the estimated size-dependent functions support hypotheses regarding the mechanisms leading to survival or emigration responses of Atlantic salmon and other stream-dwelling salmonids. © American Fisheries Society 2011. Source

Harvey R.W.,U.S. Geological Survey | Metge D.W.,U.S. Geological Survey | LeBlanc D.R.,U.S. Geological Survey | Underwood J.,U.S. Geological Survey | And 4 more authors.
Journal of Environmental Quality | Year: 2015

This study focused on the importance of the colmation layer in the removal of cyanobacteria, viruses, and dissolved organic carbon (DOC) during natural bank filtration. Injection-andrecovery studies were performed at two shallow (0.5 m deep), sandy, near-shore sites at the southern end of Ashumet Pond, a waste-impacted, kettle pond on Cape Cod, MA, that is subject to periodic blooms of cyanobacteria and continuously recharges a sole-source drinking-water aquifer. The experiment involved assessing the transport behaviors of bromide (conservative tracer), Synechococcus sp. IU625 (cyanobacterium, 2.6 ± 0.2 μm), AS-1 (tailed cyanophage, 110 nm long), MS2 (coliphage, 26 nm diameter), and carboxylate-modified microspheres (1.7 μm diameter) introduced to the colmation layer using a bagand- barrel (Lee-type) seepage meter. The injectate constituents were tracked as they were advected across the pond water- groundwater interface and through the underlying aquifer sediments under natural-gradient conditions past push-point samplers placed at ~30-cm intervals along a 1.2-m-long, diagonally downward flow path. More than 99% of the microspheres, IU625, MS2, AS-1, and ~44% of the pond DOC were removed in the colmation layer (upper 25 cm of poorly sorted bottom sediments) at two test locations characterized by dissimilar seepage rates (1.7 vs. 0.26 m d-1). Retention profiles in recovered core material indicated that >82% of the attached IU625 were in the top 3 cm of bottom sediments. The colmation layer was also responsible for rapid changes in the character of the DOC and was more effective (by three orders of magnitude) at removing microspheres than was the underlying 20-cm-thick segment of sediment. © 2015 American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. Source

Stokes A.N.,Utah State University | Cook D.G.,Sonoma County Water Agency | Hanifin C.T.,Stanford University | Brodie III E.D.,University of Virginia | Brodie Jr. E.D.,Utah State University
American Midland Naturalist | Year: 2011

Newts of the genus Taricha have long been studied in regards to their skin toxin, tetrodotoxin (TTX). It has been shown that the TTX levels across populations of Taricha are highly variable, and this has been mostly attributed to the interaction between Taricha and their only documented predators, garter snakes of the genus Thamnophis. Here we show that predators other than Thamnophis prey extensively on some newt populations. Ledson Marsh in Annadel State Park in Santa Rosa, CA is a breeding ground for both the California newt (Taricha torosa) and the rough-skinned newt (Taricha granulosa). Predation on these newts was tracked from 1998-2009 and was most often in the form of evisceration and significantly male-biased. As TTX seems to have been developed as an antipredator defense in Taricha, we used Fluorometric High Phase Liquid Chromatography (HPLC) analysis to quantify TTX levels in the skin of ten male and ten female newts of each species to determine the influence that TTX levels may have on sex-biased predation in this population. We found Taricha females were not significantly more toxic than males. Also, we found that T. torosa were significantly more toxic than T. granulosa, which is in contrast with other newt toxicity studies. © 2011 American Midland Naturalist. Source

Hidaka C.E.,IBM | Jasperse J.,Sonoma County Water Agency | Kolar H.R.,IBM | Williams R.P.,Green Innovations
IBM Journal of Research and Development | Year: 2011

Water resource management, delivery, and research are inhibited by fragmented data sources. It is nearly impossible for public officials to make informed planning decisions that benefit water wholesalers, retailers, and consumers or to efficiently operate water systems beyond their physical and organizational boundaries. Organizations operate water systems within their service areas in ways that may be suboptimal for the sustainable management of the resource as a whole. The organizations make decisions on the basis of available data, which may be incomplete or in the wrong spatial or temporal scale. Data is not shared with other organizations whose decisions and conclusions could be improved with more complete information. This can lead to more complex and fragmented water management decision-making processes that do not address the entire water resource. Sonoma County Water Agency (SCWA) in California and the SmartBay project in Ireland use advanced information technology to create collaboration platforms enabling multi-organizational management of water resources, based on information availability and sharing. While SCWA is deploying such a platform for pilot testing in early 2011 and SmartBay has been operating since late 2008, both projects provide the opportunity to overview the core components and technologies of collaboration platforms and the qualitative benefits (environmental, economic, financial, and political) that can result for water resource management. © 2011 by International Business Machines Corporation. Source

News Article | November 16, 2015
Site: http://www.greenbiz.com/

The Sonoma County Water Agency is pulling out all the stops on wise water use — deploying technologies and encouraging users to conserve.

Discover hidden collaborations