South Fork Shenandoah River habitat-flow modeling to determine ecological and recreational characteristics during low-flow periods

Abstract

The authors thank the cooperators, Northern Shenandoah Valley Regional Commission and Central Shenandoah Planning District and localities therein, for support of this scientific work. Virginia Commonwealth University contributed equipment, travel funds, and supplies as well as in-kind services for this cooperative investigation to develop the fish habitat-suitability criteria. The continued interest and feedback received from policymakers, planners, utility managers, State agency staff, and private citizens enhanced the study process. Appreciation is extended to local landowners for allowing access to the river from their properties. John Gibson of the Downriver Canoe Company allowed access to the campgrounds that accommodated the field staff. Vital field assistance was provided by our lead technician for the project, Dennis Adams (USGS, Marion, Virginia) as well as volunteers from nonprofit organizations, State agencies, universities, and private citizens. Thanks to field volunteers:

Application of a New Species‐Richness Based Flow Ecology Framework for Assessing Flow Reduction Effects on Aquatic Communities

“…Regardless of 10% or 20% flow reductions, the summer‐month ratios were fairly stable because percent change in habitat and species richness increased in magnitude at constant rates with greater flow reductions. Like other habitat studies (Krstolic et al 2006; Krstolic and Ramey 2012), we found that smaller streams had greater sensitivity to flow alteration resulting in percent change in habitat or richness. The August percent change in species richness: percent change in habitat models had a positive correlation, but were not statistically significant (corr = 0.3327, p = 0.5194; Table 3).…”

“…Percent habitat change for all species studied was negative (indicating habitat loss) in August, September, and October (Figure ). Across all IFIM sites, August and September flows had the greatest rates of habitat loss with flow reduction, further supporting the use of August flows as an indicator of risk of habitat loss or richness change (Krstolic et al 2006; Armstrong et al 2011; Kennen et al 2012; Krstolic and Ramey 2012; Knight et al 2014; Commonwealth of Virginia 2015; McManamay and Frimpong 2015; Rapp and Reilly 2017). With a 20% flow reduction, most of the IFIM sites with MAF <900 ft 3 /s had a median habitat‐loss condition in August, and the majority of IFIM sites with MAF >900 ft 3 /s had a median habitat‐gain (Figure 6).…”

“…See Kleiner et al (2020) We compiled and processed habitat information for 24 IFIM sites throughout Virginia to assess habitat change associated with monthly flow reductions. At IFIM sites (Figure 1; Table S1) analyses were conducted to validate the ELF approach with previously published habitat models that report habitat area for a given streamflow (Maryland Department of Natural Resources 1981;Leonard et al 1986;Averett et al 2004;Krstolic et al 2006;Gore 2006;Thomas R. Payne and Associates 2008;EA Engineering, Science, andTechnology Inc 2009, 2012;Krstolic and Ramey 2012). Percent change in habitat was calculated using MAF, MMF, and 10 th percentile flows for 24 IFIM sites ranging from 192 to 5,000 mi 2 encompassing streams within the range represented by the RCC ELFs and larger.…”

“…Virginia six‐digit hydrologic unit classifications (HUC 6) and HUC 8 watersheds with Instream Flow Incremental Methodology (IFIM) study site locations (IFIM site numbers relate to site information in Table . Site information and habitat information from published studies: Leonard et al (1986); Maryland Department of Natural Resources (1981); Averett et al (2004); Krstolic et al (2006); Gore (2006); Thomas R. Payne and Associates (2008); EA Engineering Science and Technology Inc (2009); Krstolic and Ramey (2012). …”

Effects of streamflows on stream-channel morphology in the eastern Niobrara National Scenic River, Nebraska, 1988–2010

“…Flow-duration curves indicate how likely it is that a particular streamflow magnitude will take place during a particular period (Krstolic and Ramey, 2012) and represent cumulative percentiles of streamflow. Flow-duration curves were calculated using USGS tools within the TIBCO Spotfire S+® software package (S+; TIBCO Software, Inc., 2008).…”