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• 1. [Article] Reviving Whychus Creek: Averting Collisions between the Endangered Species Act and Agricultural Water Use through Proactive Streamflow Restoration

  In the wake of policies catalyzing settlement through agrarian-based land ‘improvement’, private property rights absorbed water resources through Western water law. Consequently, these dominant user regimes ...

  Citation × Citation Citation Abstract Copy Title: Reviving Whychus Creek: Averting Collisions between the Endangered Species Act and Agricultural Water Use through Proactive Streamflow Restoration Author: Dengel, Jeff In the wake of policies catalyzing settlement through agrarian-based land ‘improvement’, private property rights absorbed water resources through Western water law. Consequently, these dominant user regimes and the doctrine of prior appropriation allocated nearly 80 percent of freshwater resources to agricultural use. Following enactment of the Endangered Species Act (ESA) in 1973 agricultural water users and the federal government were set on a collision course, as private property was now subject to regulatory imposition. Within Western states water bodies contiguous to private agrarian lands host the majority of aquatic species listed under the ESA. Of all the effects associated with agricultural water use, streamflow depletion constitutes the primary source of species imperilment. Customary irrigation practices often dewater streams completely or render aquatic habitat inhospitable. Consequently, curtailment of water use is increasingly sought during enforcement of ESA regulations. Encounters between ESA regulation and impositions upon agricultural water use are largely reactionary, litigious, and costly; this begs the question of remedy. Responses attending to the matter indicate collaborative and precautionary measures as prospective solutions. Within the context of streamflow-based habitat modification the answer consistently indicates transactional mechanisms reallocating water to instream use. Due to priority-based allocation developed through the doctrine of prior appropriation acquisition of senior water rights is imperative for streamflow restoration. Within Oregon's Whychus Creek agricultural water users employed a series of water right transactions serving to bolster instream flow to avert ESA regulation. Many of these transactions have been implemented through Oregon's Conserved Water Program; a unique statute providing benefits for the environment and agricultural water users alike. Through these transactions senior water rights have been reallocated to instream use and are being met, resulting in a robust presence of instream flow. Title: Reviving Whychus Creek: Averting Collisions between the Endangered Species Act and Agricultural Water Use through Proactive Streamflow Restoration Author: Dengel, Jeff In the wake of policies catalyzing settlement through agrarian-based land ‘improvement’, private property rights absorbed water resources through Western water law. Consequently, these dominant user regimes and the doctrine of prior appropriation allocated nearly 80 percent of freshwater resources to agricultural use. Following enactment of the Endangered Species Act (ESA) in 1973 agricultural water users and the federal government were set on a collision course, as private property was now subject to regulatory imposition. Within Western states water bodies contiguous to private agrarian lands host the majority of aquatic species listed under the ESA. Of all the effects associated with agricultural water use, streamflow depletion constitutes the primary source of species imperilment. Customary irrigation practices often dewater streams completely or render aquatic habitat inhospitable. Consequently, curtailment of water use is increasingly sought during enforcement of ESA regulations. Encounters between ESA regulation and impositions upon agricultural water use are largely reactionary, litigious, and costly; this begs the question of remedy. Responses attending to the matter indicate collaborative and precautionary measures as prospective solutions. Within the context of streamflow-based habitat modification the answer consistently indicates transactional mechanisms reallocating water to instream use. Due to priority-based allocation developed through the doctrine of prior appropriation acquisition of senior water rights is imperative for streamflow restoration. Within Oregon's Whychus Creek agricultural water users employed a series of water right transactions serving to bolster instream flow to avert ESA regulation. Many of these transactions have been implemented through Oregon's Conserved Water Program; a unique statute providing benefits for the environment and agricultural water users alike. Through these transactions senior water rights have been reallocated to instream use and are being met, resulting in a robust presence of instream flow. Close

• 2. [Article] A Kalman Filter Approach to Estimating Marine Turtle Incidental Take Risk

  A principle U.S. fisheries management concern is ensuring compliance with Endangered Species Act requirements to limit incidental takes of listed species to levels which do not result in potential jeopardy ...

  Citation × Citation Citation Abstract Copy Title: A Kalman Filter Approach to Estimating Marine Turtle Incidental Take Risk Author: Stohs, Stephen, Kvamsdal, Sturla A principle U.S. fisheries management concern is ensuring compliance with Endangered Species Act requirements to limit incidental takes of listed species to levels which do not result in potential jeopardy to existing population stocks. Part of the risk assessment process involves an analysis of historic takes (bycatch) of ESA-listed species relative to fishing effort. Sample bycatch per unit of effort (BPUE) ratios are used to gauge the take risk to ESA-listed species posed by future fishing effort. The rare-event nature of protected species takes complicates the interpretation of sample BPUE ratios. For illustration, a total of 23 leatherback turtles were incidentally taken by fishermen in the California-Oregon drift gillnet fishery from the 1990 through 2006 fishing seasons in 7733 sets of fishing effort, with from 0 to 5 leatherback takes per season over the entire period. Should one conclude the incidental take risk was significantly higher during the season with 5 leatherback turtle takes than in seasons with 0 takes? To address this and related inference problems, we specify a state space model which describes the pattern of observed takes as a Poisson process conditional on the level of fishing effort. A time-varying Poisson rate parameter, expressed as BPUE, measures the time-varying level of take risk. A Kalman filter for Poisson processes is used to estimate the intertemporal variation in take risk from California-Oregon drift gillnet fishery observer data. A key question regards attributing the observed pattern of takes to randomness which drives fluctuations in observed takes versus intertemporal variation in the level of take risk. Title: A Kalman Filter Approach to Estimating Marine Turtle Incidental Take Risk Author: Stohs, Stephen, Kvamsdal, Sturla A principle U.S. fisheries management concern is ensuring compliance with Endangered Species Act requirements to limit incidental takes of listed species to levels which do not result in potential jeopardy to existing population stocks. Part of the risk assessment process involves an analysis of historic takes (bycatch) of ESA-listed species relative to fishing effort. Sample bycatch per unit of effort (BPUE) ratios are used to gauge the take risk to ESA-listed species posed by future fishing effort. The rare-event nature of protected species takes complicates the interpretation of sample BPUE ratios. For illustration, a total of 23 leatherback turtles were incidentally taken by fishermen in the California-Oregon drift gillnet fishery from the 1990 through 2006 fishing seasons in 7733 sets of fishing effort, with from 0 to 5 leatherback takes per season over the entire period. Should one conclude the incidental take risk was significantly higher during the season with 5 leatherback turtle takes than in seasons with 0 takes? To address this and related inference problems, we specify a state space model which describes the pattern of observed takes as a Poisson process conditional on the level of fishing effort. A time-varying Poisson rate parameter, expressed as BPUE, measures the time-varying level of take risk. A Kalman filter for Poisson processes is used to estimate the intertemporal variation in take risk from California-Oregon drift gillnet fishery observer data. A key question regards attributing the observed pattern of takes to randomness which drives fluctuations in observed takes versus intertemporal variation in the level of take risk. Close