Environmental Flows: What, why, case studies and more

Transcription

1 Environmental Flows: What, why, case studies and more Daniel D. Magoulick U.S. Geological Survey Arkansas Cooperative Fish & Wildlife Research Unit Department of Biological Sciences University of Arkansas

2 What are environmental flows? ELOHA approach Case studies Susquehanna River conceptual model Michigan ELOHA approach Massachusetts hybrid approach Our e-flow study in AR Flow classification Hydrology-biology relationships Outline

3 What are Environmental flows? Definition Stream flows required to maintain the function of particular organisms in a system or overall ecosystem structure and function (Poff et al. 2010) quantity, timing and quality of water flows required to sustain freshwater and estuarine ecosystems and the human livelihood and well being that depend on these ecosystems - Brisbane Declaration Naturally variable flow regime, rather than just a minimum low flow, is required to sustain freshwater ecosystems Poff et al. 1997, Bunn and Arthington 2002 Key flow components Magnitude Frequency Duration Timing Rate of change

4 Environmental Flows Flows of water in streams affect freshwater organisms and ecosystems However the relationship between them is often little studied and poorly known Application Useful tool for the conservation of freshwater resources Useful for assessing potential impacts of climate change on stream organisms and ecosystems (Xenopolous et al. 2005)

5 ELOHA Framework ELOHA (Poff et al. 2010): Ecological Limits of Hydrologic Alteration Synthesis of existing hydrologic techniques and environmental flow methods to support comprehensive regional flow management Ecologically based and socially acceptable goals and standards.

6 Key flow components Magnitude Frequency Duration Timing Rate of change Hydrologic Foundation

7 Missouri Flow Classification Study Kennen et al Classify Flow Types

8 Carlisle et al Determine Flow Alteration Flow alteration deviation of observed flow from expected natural flow

9 Arthington et al Flow-Ecology Relationships

10 Poff et al Example 1 Change in low flow duration and native fish production in a stable groundwater-fed stream

11 Poff et al Example 2 Change in high flow frequency and non-native fish success in a naturally flashy stream

12 Carlisle et al. 2010

13 Case Studies

14 Susquehanna River Basin Ecosystem Flow Recommendations Expert opinion and conceptual models Graph showing ecological functions that depend on typical low, seasonal, and high flows during fall, winter, spring, and summer for one habitat type (Major Tributaries) in the Susquehanna River basin. A similar graph for each habitat type greatly facilitated development of flow recommendations in an expert workshop.

15 Michigan Water Withdrawal Assessment process ELOHA approach (hydrologic foundation, river classification, flow alteration, flowecology relationships, social process) Typical fish-response curves. ARI indicates Adverse Resource Impact, depicted here as 90% of characteristic fish species remaining, as recommended by the Advisory Committee. Light lines indicate thresholds between water management zones associated with different degrees of ecological change. A = register water use, B = notify local water users, C = form a water user committee.

16 Michigan Water Withdrawal Assessment process Michigan s fish response curves, showing how each type of river has different curves, and therefore different water withdrawals associated with each management zone. From Zorn et al. (2008).

17 Massachusetts Sustainable Water Management Initiative ELOHA mostly Examples of flow-ecology curves for Massachusetts showing quantileregression relationships between fish-community metrics and August flow depletion. From Armstrong et al. (2011).

18 Massachusetts Sustainable Water Management Initiative Massachusetts draft streamflow criteria structure (February 3, 2012 version). Flow-ecology curves relating fluvial fish communities to percent flow alteration in August from groundwater withdrawal informed the development of these proposed criteria. From Massachusetts Executive Office of Energy and Environmental Affairs (2012).

19 Our Study ELOHA approach in Arkansas and surrounding region

20 Classify stream types within Arkansas and surrounding region based on hydrology Examine hydrology-biology response relationships within flow classes State-wide Based on existing data Develop regional level hydrology-biology response relationships for a portion of the Ozarks Ozark Highlands ecoregion Single flow class Comparative field study Objectives

21 Results and Benefits Investigate environmental flows in Arkansas and surrounding region Develop detailed ecological flow-response relationships to form the basis of state and regional environmental flow standards Provide methodologies to apply to other regions Use environmental flow relationships to understand potential impacts of climate change Provide basis for conservation of at least 31 fish, crayfish, and insect species of greatest conservation need

22 Hydrologic Foundation Selection of streamflow gages in Arkansas, Missouri and Oklahoma Determine least-altered landscapes, river networks, and flow regimes Use of Falcone et al GAGES data paper in Ecology Hydrograph properties Magnitude Duration Frequency Timing Rate of Change

23 Addition of Missouri and Oklahoma gages 230 gages with streamflow measurements and 15 year period of record USGS Gages

24 Flow Variables Used in Classification Mean streamflow Q01, 10, 25, 50, 75, 90, 99 50th percentile of absolute value of percent daily change CV of daily flows CV of log-transformed daily flows CV of log-trans annual max flow Median annual maximum flow Qmax/Q50 Median annual # high-flow events Median duration of the annual longest high-flow event # mos prob >0.5 of high-flow event Mode of highest stream flow month Median annual minimum flow Qmin/Q50 CV of annual minimum flow Median # low-flow periods Median dur of ann longest low-flow # mos prob >0.5 of low-flow period Mode of lowest flow month Fraction of years with no-flow days Mean number of no-flow days in years with no-flow days CV of annual mean flow Storm-flow recession coefficient Base-flow recession coefficient Maximum monthly flow Minimum monthly flow Maximum CV of monthly flow Minimum CV of monthly flow Normalized range of monthly flow LOG(Q10/Q90) Hydroperiod

25 Reference gage selection Hydrologic Disturbance Index Seven variables: Major dam density Water withdrawals Change in dam storage ( ) Percent canals in watershed Distance to nearest NPDES Road density Fragun basin In addition, < 10% urban land-use Agricultural land-use assessment No major dams Manual removal of gages on or adjacent to reservoirs/dams

26 61 gages satisfying reference criteria Reference Gages

27 Classification of Flow Regimes K-means clustering Apriori number of clusters Reduces within-group sums of squares (like MANOVA in which groups not known) K-means does not have any spatial structure Sensitive to outliers and order of observations Concordance with ecoregions? i.e. Do groupings makes sense based on what we know about Arkansas streams?

28 Determination of Class Number MRPP: Permutation test for differences between or among groups of sample units based on within group similarities Measure of the effect size (A), known as the within group agreement provides an indication of how similar the sample units within a group are to one another Average Chance-corrected within group agreement (MRPP 'A') Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 Group 9

29 Six Flow Classes

30 Future Work Define flow classes and model flow variables across all gage sites Use climate, topography and land use/land cover variables to model flow at un-gaged sites Examine hydrology-biology response relationships within flow classes State-wide Based on existing data Develop regional level hydrology-biology response relationships for a portion of the Ozarks Ozark Highlands ecoregion Springfield Plateau Single flow class Comparative field study Forecast effects of climate change on flow

31 Acknowledgements: Funding Agencies: Arkansas Game and Fish Commission Data Collection Assistance: Dustin Lynch Brie Olsen Jared Schluterman Kelsey Deal Alexa Kusmik Keith Waters Tyler Williams