Status Ecological Flows in NC and Complications of Being on the Coast. Bob Christian East Carolina University Greenville, North Carolina USA

Transcription

1 Status Ecological Flows in NC and Complications of Being on the Coast Bob Christian East Carolina University Greenville, North Carolina USA

2 Outline NC Ecological Flows and Science Advisory Board (EFSAB) Activities and main recommendations of EFSAB and status of effort Coastal complications & APNEP efforts

3 Ecological Flows Science Advisory Board ( ) Help NC DENR with planning efforts on water flow modifications and impact. Provide advice on ways to use ecological flows in planning

4 Legislation defined ecological flows A flow regime that protects ecological integrity is often referred to as an ecological flow

5 Legislation defined ecological integrity the ability of an aquatic system to support and maintain a balanced, integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to prevailing ecological conditions and, when subject to disruption, to recover and continue to provide the natural goods and services that normally accrue from the system.

6 Final Report (

7 Overview of SAB activities Stream classification Hydrological models Flow vs habitat relationships Approaches by other states Indices of selected community structure related to flow

8 Overview of SAB activities Stream classification weak associations with ecology limited basin-level distinctions Hydrological modeling basis for future conditions Flow vs habitat relationships limited opportunities Approaches by other states often % flow criteria Indices of selected community structure related to flow statistical support acceptable Limitations coastal systems, headwaters

9 Hydrological Models to Estimate Flows (future ~20 years) Oasis Patented, mass balance, water resources simulation/optimization model DWR invested Based on long-term gage records and environmental factors Basin-wide

10 Hydrological Models to Estimate Flows Waterfall (RTI model) new watershed modeling tool and decisionsupport platform to enable inter-active quantitative investigation of water availability and allocation at multiple geographic scales Driven by ppt and environmental/watershed properties more explictly.

11 Two Recommended Approaches Recommended ways to determine if future projected water modifications warrant further assessment by DWR Percentage-of-flow strategy Biological-response strategy

12 Two Recommended Approaches Percentage-of-flow strategy: In the basinwide hydrologic models, DWR should use 80-90% flow-by combined with a critical low flow component as the ecological flow threshold. If the models indicate that there is insufficient water available to meet all needs, essential water uses and ecological flows, then further review by DENR is recommended.

13 Percentage predicted flow by criteria with critical threshold

14 Two Recommended Approaches Biological-response strategy: DWR should use a 5-10% reduction in biological condition (A) Shannon-Weaver Index for fish diversity and (B) number of taxa in the orders of mayflies, stoneflies, and caddisflies for invertebrates as a threshold for initiating further review. Efforts by RTI and USGS

15 Figure 9. Ecodeficits are calculated by measuring reductions in flow between altered and unaltered flow duration curves.

16 Figure 10A. Quantile regression (0.8 quantile) showing the relation between summer ecodeficit and riffle-run fish guild Shannon-Weaver Diversity Index (greyed area indicates 95% confidence interval)

17 Ruling of Environmental Management Commission The Department of Environment and Natural Resources is authorized and directed to work with the General Assembly to specifically resolve the inconsistent and incompatible uses of the term ecological flow in General Statute section (o)(3)and (4). Until such time that such issue is resolved, the hydrologic models for the Tar River Basin, the Roanoke River Basin and the Cape Fear River-Neuse Basin are not approved. Until such time that such issue is resolved, the Department is authorized to continue to use the Tar River Basin, the Roanoke River basin and the Cape Fear-Neuse River Basin hydrologic modes in planning decisions and, as required in order to comply with required statutes or rules, to make decisions on permit applications or other matters concerning water allocations; PROVIDED THAT any determination required by General Statute section (o)(3)(b) 1, 2, and 3 shall be based on site specific data and shall not be based on any generally applicable standard or value, including but not limited to any generally applicable standard or value for ecological flow contained in or derived from the report entitled Recommendations for Estimating Flows to Maintain Ecological Integrity in Streams and Rivers in North Carolina dated November 2013.

18 Challenges of Coastal Waterways (Begun with EFSAB and continued with APNEP)

19 APNEP s Flows Workgroup Charge (based on its CCMP) Action A3.3: Develop and refine ecological flow requirements for each major river. Action D3.2: Facilitate the development and implementation of basinwide water management plans to ensure no less than minimum instream flows are maintained.

20 Three overarching concerns that may challenge application of approaches to coastal plain: Hydrogeomorphological issues influencing modeling Ecological issues influencing choice of ecological integrity choices Human impact issues

21 Hydrogeomorphology: the area is flat!! Slope is low Flow often not high enough to move heavy material and scour Riffle and pool structure with rocks less common Bottom often muddier

22 Hydrogeomorphology: the area is flat!! Reverse flow is common Tidal action Backflow from larger rivers during high flows Few gaging stations

23 Hydrogeomorphology: the area is low!! Gaging stations are limited

24 Without gaging stations hydrological models fail

25 Hydrogeomorphology: the area is flat!! Topographic relief makes watershed designations difficult High connectivity with adjacent wetlands From Riggs and Ames

26 Hydrogeomorphology: the area is low!! Salinity May range from 0 to >30 May be affected by water use

27 Hydrogeomorphology: the area is low!! Sensitivity to sea-level rise

28 Established habitat-based foundation through the Coastal Habitat Protection Plan (CHPP) developed by NC DMF Habitats germane to EFSAB Ecology

29 Ecology Species are often different than those found in inland waters or have different ecology from that inland. Examples (Some require Fisheries Management Plans involving flows) Anadromous fish (upstream spawning) Blueback herring and alewife (under consideration for endangered status) American shad Atlantic sturgeon (endangered) Shortnose sturgeon (endangered) Striped bass (stock status concern) Catadromous fish (marine spawning)- eel (stock status - depleted) Estuarine species some of the common low-salinity species that occur in river systems: southern flounder, Atlantic croaker, spot, menhaden, bay anchovy, blue crab, white shrimp, striped mullet

30 Table 2.4. Physical spawning (adult) and egg development requirements for resident freshwater and anadromous fishes inhabiting coastal North Carolina. Physical factors and flow influence select species and life history stages Species Alewife [S] 0-5 American shad Blueback herring Striped bass Yellow perch White perch Sturgeon, Atlantic Salinity (ppt) Spawn/ Adult Egg [S] 0-5 [O] 0-2 [S] 0-18 [S] 0-18 [S] [S] 0-5 [S] 0-22 [O] 0-2 [S] 0-5 [S] [S] Temperature (C) Spawn/ Adult Egg [S] [O] [S] [S] [O] [S] 12-24, [O] ~18-22 Dissolved oxygen (mg/l) Adult [S] >3.6 [S] >4 Other parameters Flow (cm/s) Spawn/ Egg Spawning Spawn/ Egg [O] slow current [S] >5 [S] [S] >5 [S] >5 [S] 0-13 [S] 0-2 [S] 6-30 [S] >5 [S] 5-18 [S] 0-2 [S] [S] [S] >5 [S] 0 to >30 [S] 0-5 [S] 0 to >30 [S] [O] strong current [S] , [O] [S] Suspended solids <1000 mg/l [S] Suspended solids <1000 mg/l [S] Suspended solids <1000 mg/l [S] Suspended solids <100 mg/l Sturgeon, Shortnose [S] 0 to >30 [S] 0-5 [S] 0 to >30 [S] 5-15 [S] = Suitable, and [O] = Optimum

31 Ecology DWQ has different programs for Index of Biotic Integrity for coastal plain streams. Hydrogeomorphology (Very low flows, channel modifications, riparian zones, depth) Biota Fish Benthic macroinvertebrates» Swamp method There is no estuarine IBI for coastal waters

32 Human alterations dominate Obstructions dams, culverts block fish passage and alter flows Channelization Agricultural ditching Road side ditching Desnagging/Snagging Navigational dredging

33 Agricultural ditching Road side ditching Channelization Snagging Navigational dredging Human alterations dominate

34 Kinds of water withdrawal issues Community water supply Not necessarily based on surface withdrawal and reservoir use. Groundwater and desalinization Increasing demands with coastal population growth Non- community water supply Mining Agriculture Industry (power plants)

35 Water Use

36 Summary Coastal plain waterways are potentially different in numerous ways: Hydrogeomorphological issues influencing modeling Ecological issues influencing choice of ecological integrity choices Kinds of water withdrawals All of these contribute to the challenge of applying procedures from inland to the coastal plain. We formed a Coastal Ecological Flows Working Group to contribute to the EF SAB.

37 Recommendations from Coastal Ecological Flows Working Group

38 Overall Objectives Assess applicability of previous coastal work Develop stream typology Advance spatial modeling & mapping Establish relevant ecological & biological dependencies on flow Identify factors limiting EF protocols & needed research within coastal systems Develop frameworks for potential coastal EF criteria & protocols if possible

39 by Scott Ensign

40 1 st cut recommended designations (Eban Bean and Mike Griffin) Origin by reach Evaluation of medium vs low slope cutoff Medium =>2.51 mm/m Low <= 2.50 mm/m Tidal effect is below 1 m elevation

41 from Eban Bean and Mike Griffin

42 Link between waterway category and key assemblage that could be used for ecological flow assessment.

43 Link of Stream Typology & Potential EF Determination

44 Coastal ecological flows framework The coastal EF working group effort provided a framework for future development APNEP has this issue is part of their Comprehensive Conservation Management Plan. It has formed a working group to continue work.

45 Questions? You cannot escape the responsibility of tomorrow by evading it today. - President Abraham Lincoln

46 DWR Basin Models STATUS OF DIVISION OF WATER RESOURCES BASIN MODELS BASIN MODEL KICK-OFF MEETING STATUS APPROVED BY EMC? a CAPE FEAR OASIS b October 1, 2007 AVAILABLE c NO NEUSE OASIS February 25, 2008 AVAILABLE NO CAPE FEAR-NEUSE OASIS AVAILABLE NO TAR-PAMLICO OASIS July 15, 2010 AVAILABLE NO BROAD OASIS October 7th, 2010 AVAILABLE YES (November 8, 2012) ROANOKE d OASIS August 23, 2012 AVAILABLE NO CATAWBA d CHEOPS e August 1, 2013 AVAILABLE NO YADKIN-PEE DEE d -LUMBER OASIS?,CHEOPS? 2016 UNDER DEVELOPMENT MODELS FOR FRENCH BROAD/HIWASSEE/LITTLE 2017 PRE-DEVELOPMENT TENNESSEE/WATAUGA BASINS MODELS FOR ABLEMARLE SOUND/CHOWAN/NEW/ONSLOW BAY/SAVANNAH BASINS 2018 PRE-DEVELOPMENT Provided by Fred Tarver, DWR