6/06/2017  |   11:00 - 11:15   |  302A

ALTERNATIVE MODELS OF HYDROGEOMORPHIC CONNECTIVITY IN URBANIZING PIEDMONT LANDSCAPES Urbanization studies have long posited a collection of impacts resulting from watershed hardening and stormwater routing that increase connection between upland landscapes and streams. Prevailing paradigms note a syndrome of biophysical impacts associated with increasing impervious cover, a common proxy for road and population density. Conceptual models, as well as restoration and mitigation designs inspired by this narrative, focus on hydrologic flashiness and storm flow as a mechanistic driver, despite increasing evidence that substantial biotic degradation occurs prior to detectable change in hydrologic metrics. We employed multi-temporal analysis of high-resolution topography during urbanization to reveal increases in hydrologic connectivity controlled by terrain re-sculpting and alteration of surface flow networks. We identified geomorphic signatures of network disconnection in forested landscapes found to be prevalent across broader regions, but that decreased markedly in agricultural or suburban settings. Collectively, our findings suggest increasingly connected hydrogeomorphic networks result from terrain modification or alteration of catchment water budgets independent of impervious surface at levels of urbanization far lower than previously described. Our results may indicate a need for highly distributed mitigation efforts at very low levels of land use intensity to better protect biotic assemblages.

Matthew Baker (Primary Presenter/Author), University of Maryland Baltimore County, mbaker@umbc.edu;


Daniel Jones ( Co-Presenter/Co-Author), USGS, dkjones@usgs.gov;


Ellen Woytowitz ( Co-Presenter/Co-Author), UMBC, ellen6@umbc.edu;


Andrew Miller ( Co-Presenter/Co-Author), UMBC, miller@umbc.edu;


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6/06/2017  |   11:15 - 11:30   |  302A

ESTIMATING HYDROLOGIC ALTERATION AND SETTING FLOW TARGETS THAT SUPPORT BIOLOGICAL INTEGRITY AT UNGAGED SITES IN A LARGE URBANIZED REGION We describe a novel approach to simulating flow regimes at ungaged sites and developing regional flow-ecology relationships in a large urbanized region. An ensemble of regionally calibrated and validated hydrological models was used to estimate current and reference flows at 572 sites where bioassessment samples have been collected in southern and central coastal California. Flow alteration was characterized as the difference in a suite of 36 flow metrics calculated from simulations of current and historic (i.e., reference) flow time-series under multiple precipitation conditions. An index of hydrologic alteration was created by selecting metrics based on their importance for predicting biological response variables in boosted regression tree models. Regionally derived, biologically based targets for flow alteration were developed to allow watershed managers to rapidly prioritize activities and conduct screenings for causal assessments at many sites across large spatial scales. Such regional tools pave the way for incorporating hydrologic management in policies and watershed planning designed to support biological integrity in streams.

Brian Bledsoe (Primary Presenter/Author), University of Georgia, bbledsoe@uga.edu;


Eric Stein ( Co-Presenter/Co-Author), Southern California Coastal Water Research Project, erics@sccwrp.org;


Raphael Mazor ( Co-Presenter/Co-Author), Southern California Coastal Water Research Project, raphaelm@sccwrp.org;


Stephen Adams ( Co-Presenter/Co-Author), Colorado State University, skadams89@gmail.com;


Ashmita Sengupta ( Co-Presenter/Co-Author), CSIRO, Ashmita.Sengupta@csiro.au;


Kenneth McCune ( Co-Presenter/Co-Author), Southern California Coastal Water Research Project, kennym@sccwrp.org;


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6/06/2017  |   11:30 - 11:45   |  302A

QCRITICAL AS A GEOMORPHICALLY AND BIOLOGICALLY RELEVANT FLOW THRESHOLD FOR RIVER MANAGEMENT AND RESTORATION The threshold discharge that initiates streambed mobilization (Qcritical) is one of the most mechanistically-important flows for geomorphic function and biological integrity in stream ecosystems. Increased exceedance of Qcritical is a dominant driver of geomorphic instability and excess benthic disturbance in urban/suburban streams (i.e. the urban disturbance regime). In one 7-y study, reference site macroinvertebrate communities during years with atypically frequent Qcritical events were more similar to sites draining watersheds with ~30% imperviousness than to reference site communities of more typical rainfall years. Using an international database of nearly 200 sites we show that Qcritical varies by several orders of magnitude as a function of streambed particle size. Qcritical in sand-dominated streams is likely to be orders of magnitude less than the 1-yr discharge, whereas Qcritical in cobble/boulder dominated streams could be much larger than the 1-yr discharge, implying that stormwater/restoration policies focused on the 1-yr (or “bankfull”) event could lack efficacy in many settings. Incorporating Qcritical into stream restoration and stormwater management can ensure that designs are tailored to the mechanisms that drive channel erosion and disturbance to the benthos.

Robert Hawley (Primary Presenter/Author), Sustainable Streams, LLC, bob.hawley@sustainablestreams.com;


Matthew Wooten ( Co-Presenter/Co-Author), Northern Kentucky Sanitation District No.1 (SD1), mwooten@sd1.org;


Geoff Vietz ( Co-Presenter/Co-Author), Streamology/University of Melbourne, geoff@streamology.com.au;


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6/06/2017  |   11:45 - 12:00   |  302A

RESTORING STREAM INTEGRITY THROUGH WATERSHED SCALE STORMWATER MANAGEMENT. A leading cause of degraded stream integrity (chemical, physical and biological) comes from poorly mitigated, or completely un-mitigated, storm water runoff. These altered flow regimes have accelerated stream bed mobilization and bank erosion rates, leading to losses of biodiversity and shifts in aquatic community structure, as well as damage to nearby infrastructure (roads, utilities, etc.) and private property. Recognizing these impacts, SD1 of Northern Kentucky, the regional stormwater management utility, embarked on a nearly decade long assessment that identified relevant flow thresholds (Qcritical) to local receiving streams. Using this information, pilot studies are currently underway that attempt to restore natural hydrology through the retrofitting of existing storm water management facilities (e.g. detention ponds). Through relatively simple optimization of the outlet control structures associated with these facilities, flow rates can be controlled to reduce the destabilizing impacts to receiving streams, as well as the potential restoration of base flows. This presentation will highlight the progress made to date, as well as discuss the preliminary in-stream results.

Matthew Wooten (Primary Presenter/Author), Northern Kentucky Sanitation District No.1 (SD1), mwooten@sd1.org;


Robert Hawley ( Co-Presenter/Co-Author), Sustainable Streams, LLC, bob.hawley@sustainablestreams.com;


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6/06/2017  |   12:00 - 12:15   |  302A

THE ROLE OF THE HYPORHEIC ZONE IN URBAN STREAM RESTORATION The inclusion of hyporheic design elements is an innovative, but largely untested, approach in urban stream restoration. In fall of 2014, the City of Seattle completed multiple floodplain reconnection projects intended to enhance hyporheic function in the city’s largest urban creek. To evaluate overall biological response, NOAA Fisheries monitored microbial and invertebrate community structure at restored and unrestored reaches, and at forested reference reaches. We found that taxonomic structure of both microbial and invertebrate hyporheic communities was significantly different between restored and unrestored reaches. Microbial heterotrophic production in hyporheic water was greater in restored than in unrestored reaches. Hyporheic invertebrate density and taxa richness were also higher at restored than at unrestored reaches, and comparable to reference reaches. We did not detect differences in nutrient concentrations or benthic invertebrates relative to restoration. Our results examine only the beginning portion of the restoration response trajectory. Further years of monitoring will allow us to better evaluate the role of the hyporheic zone in urban stream restoration.

Sarah Morley (Primary Presenter/Author), NOAA Fisheries, sarah.morley@noaa.gov;


Linda Rhodes ( Co-Presenter/Co-Author), NOAA Fisheries, Linda.Rhodes@noaa.gov;


Anne Baxter ( Co-Presenter/Co-Author), NOAA Affiliate, Anne.Baxter@noaa.gov;


Giles Goetz ( Co-Presenter/Co-Author), NOAA Affiliate, Giles.Goetz@noaa.gov;


Katherine Lynch ( Co-Presenter/Co-Author), City of Seattle, Katherine.Lynch@seattle.gov;


Steve Damm ( Co-Presenter/Co-Author), City of Seattle, Steve.Damm@seattle.gov;


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6/06/2017  |   12:15 - 12:30   |  302A

Biogeochemical implications of indirectly discharging treated wastewater effluent into the floodplain Wastewater treatment plants traditionally discharge treated effluent directly into rivers, but some plants have started discharging into floodplains along rivers to support broader ecosystem service benefits. This indirect discharge may facilitate floodplain restoration, wastewater reuse, and enhance nutrient retention. Unfortunately, there is little data available to examine concerns that indirect discharge will contaminate drinking water or increase floodplain nutrient loads. We addressed these concerns by monitoring groundwater and surface water before, during, and after both floodplain restoration and overland discharge into the Yakima River floodplain. After a year of indirect discharge, we have found that effluent primarily increases nutrient concentrations in groundwater and surface waters near (within 50m) and directly down gradient of effluent, indicating low risk of drinking water contamination or floodplain degradation in the short term. However, we also found little evidence that effluent quality improves as it travels through surface waters of the floodplain to the river. We suggest that both the risk to drinking water and potential for improvements in effluent quality require a hydrologically-informed understanding of biogeochemistry and groundwater surface water interaction in the floodplain.

Charlotte Narr (Primary Presenter/Author), Colorado State University, charlottenarr@trentu.ca;


Mike Price ( Co-Presenter/Co-Author), City of Yakima, Mike.Price@yakimawa.gov;


Ann Keeley ( Co-Presenter/Co-Author), U.S. EPA, keely.ann@epa.gov;


Bart Faulkner ( Co-Presenter/Co-Author), U.S. EPA, Faulkner.bart@epa.gov;


Harsh Singh ( Co-Presenter/Co-Author), U.S. EPA, singh.harsh@epa.gov;


Doug Beak ( Co-Presenter/Co-Author), U.S. EPA, beak.doug@epa.gov;


Paul Mayer ( Co-Presenter/Co-Author), United States Environmental Protection Agency, mayer.paul@epa.gov;
Dr. Paul Mayer is an Ecologist at the U.S. Environmental Protection Agency.

Kenneth Forshay ( Co-Presenter/Co-Author), U.S. EPA, forshay.ken@epa.gov;


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