Quantifying Quantifying fragmentation of fragmentation of

freshwater systems freshwater systems using a measure of using a measure of

discharge discharge modification (and modification (and

other applications)other applications)David Theobald, John Norman, David Theobald, John Norman, David Merritt (USFS)David Merritt (USFS)

Natural Resource Ecology Lab, Dept of Natural Resource Ecology Lab, Dept of Recreation & Tourism, Colorado State Recreation & Tourism, Colorado State UniversityUniversity

Fort Collins, CO 80523 USA Fort Collins, CO 80523 USA 26 July 26 July 20052005

Freshwater Freshwater fragmentationfragmentation

Southern Rockies Ecosystem Project. 2000.

Fragmentation and flow Fragmentation and flow modificationmodification

Deynesius and Nilsson Deynesius and Nilsson (1994) – 77% of upper (1994) – 77% of upper 1/3 of northern 1/3 of northern hemisphere rivers are hemisphere rivers are strongly or moderately strongly or moderately affectedaffected- - F = regulated/total F = regulated/total channel lengthchannel length- R = % of VMAD - R = % of VMAD (cumulative reservoir live, (cumulative reservoir live, gross capacity)gross capacity)

RegulatedChannelLength(RCL) Total

Channel Length(TCL)

Network-based flow Network-based flow modificationmodificationDegree of modification (Degree of modification (FF) is ratio of unmodified discharge ) is ratio of unmodified discharge

as a proportion of total annual dischargeas a proportion of total annual dischargeF = ( Q-S ) / Q F = ( Q-S ) / Q - QQ is cumulative annual discharge is cumulative annual discharge- SS is cumulative dam “normal” storage is cumulative dam “normal” storage

Predicted dischargePredicted discharge

Average annual Average annual precipitation & precipitation & temperature, basin temperature, basin areaarea

Vogel et al. 1999Vogel et al. 1999

Vogel

Discharge map of USDischarge map of US

National Inventory of National Inventory of DamsDams ~80,000; >4 m height~80,000; >4 m height

Map of damsMap of dams

Thanks!Thanks! Comments? Questions?Comments? Questions? Funding/Disclaimer: The work reported Funding/Disclaimer: The work reported

here was developed under the STAR here was developed under the STAR Research Assistance Agreement CR-Research Assistance Agreement CR-829095 awarded by the U.S. 829095 awarded by the U.S. Environmental Protection Agency (EPA) Environmental Protection Agency (EPA) to Colorado State University. This to Colorado State University. This presentation has not been formally presentation has not been formally reviewed by EPA.  The views expressed reviewed by EPA.  The views expressed here are solely those of the presenter here are solely those of the presenter and STARMAP, the Program (s)he and STARMAP, the Program (s)he represents. EPA does not endorse any represents. EPA does not endorse any products or commercial services products or commercial services mentioned in this presentation.mentioned in this presentation.

FLoWS: FLoWS: www.nrel.colostate.edu/pwww.nrel.colostate.edu/projects/starmaprojects/starmap

davet@nrel.colostate.edudavet@nrel.colostate.edu

CR - 829095