Data for: Mimicking functional elements of the natural flow regime promotes native fish recovery in a regulated river

Environmental flows are essential to the conservation of riverine biodiversity, and are increasingly designed to protect components of the flow regime that support critical ecosystem functions. Yet, few studies have quantified biological responses to individual components of environmental flows. We used multivariate autoregressive state-space (MARSS) models to analyze 25 years of fish assemblage data collected before and after court-ratified environmental flows were implemented in Putah Creek, a dammed stream in California, USA. We quantified functional components of the flow regime that have been identified for Mediterranean climate regions of western North America and identified changes in these components from before to after the environmental flow regime was implemented. Additionally, we compared these values to their predicted natural ranges and modeled the probability of native and non-native fish assemblages declining by > 80% (quasi-extinction risk) under alternative manageme..., Fish dataset
The fish assemblage of Putah Creek was sampled annually by TRPA Fish Biologists and Normandeau Associates between 1993 and 2019 (with the exception of 2009 and 2011) using single-pass tote barge electrofishing. Fish were sampled at six locations downstream of the Putah Creek diversion dam. For these analyses, we restricted the sites considered to only the four sites closest to the diversion dam. These sites (site codes PDD, I505, STEVE, and PED) were approximately 0, 6, 16, and 21 km downstream of the diversion dam (respectively). Previous research found that the lower two sites (25 and 30 km downstream of the dam) were minimally affected by environmental flows implementation due to degraded habitat conditions (Kiernan et al. 2012).
Functional flow metric calculations
Discharge data from the Putah Creek diversion dam were provided by the US Bureau of Reclamation for 7/1/1975 – 8/31/202. All functional flow metrics were calculated on 40 years of streamflow data, spanning the..., ,