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Ecosystem Flows Hydrology and Connectivity

Ecosystem Flows Hydrology and Connectivity. Joe Trungale October 2, 2006. Organization. Sustainable Rivers Program to Caddo Watershed and Building Blocks Recommendations Hydrology and Connectivity Review of building block recommendations and research priorities.

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Ecosystem Flows Hydrology and Connectivity

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  1. Ecosystem FlowsHydrology and Connectivity Joe Trungale October 2, 2006

  2. Organization • Sustainable Rivers Program to Caddo Watershed and Building Blocks Recommendations • Hydrology and Connectivity • Review of building block recommendations and research priorities. • Status report of on-going work. • Strategy for refinements to flow recommendations and research priorities. • Little and Black Cypress

  3. Process to Develop Ecosystem Flow Recommendations December 2004 On-going April 2005 May 2005

  4. Ecosystem Flow Components • Flow prescription considers the • flow regime (Large Floods, Small Floods, High Flow Pulses, Low Flows, and Extreme Low Flows) • inter-annual variation (wet, normal and dry years) • riverine and lake components (hydrology, biology, geomorphology, water quality and connectivity) • measures (magnitude, frequency, duration, timing and rate of change) • ecosystem response

  5. Instream Flow Building Blocks Big Cypress Creek/ Caddo Lake Key Wet Year Avg Year Dry Year 6,000-10,000 cfs for 2-3 days Every 3-5 years *Maintain aquatic habitat in floodplain * Riparian seed dispersal * Inhibition of upland vegetation for both creek & lake *Seed dispersal * Vegetation removal 20,000 cfs for 2-3 days Every 10 years *For channel migration Floods 6,000 cfs for 2-3 days Every 2 years * For channel maintenance High Flow Pulses • 1,500 cfs for 2-3 days • 3-5X a year every year • * 1 occurring in March for Paddlefish • * Sediment transport, oxbow connectivity • Waterfowl habitat flushing • (Includes December) Low Flows 40 – 536 cfs Maintain biodiversity and connectivity (backwater & oxbows) 268-347 cfs Pre-dam median 390 - 79 cfs Benthic drift & dispersal, fish spawning 35 - 40 cfs Fish habitat 40 - 117 cfs Pre-dam median 90 cfs Fish habitat 218 – 49 cfs Spawning habitat 13 - 6 cfs Maintain aquatic diversity 40 - 90 cfs Fish habitat JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

  6. Lake Level Building Blocks Caddo Lake Elevated Lake Level Inhibition of upland vegetation Refill for Nutrient and sediment flush Duration: about 15 days Normal Lake Level Low Lake Level Summer draw down to prepare for nutrient flush. Duration: every year for 1 ten year period This chart is based on the assumption that the lake would benefit from nutrient flushing. Unknown’s include (but are not limited to) the quality of the refill water, impacts and on aquatic species and how long it will take to drop down. This idea is currently “parked” JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

  7. Hydrology • Stream gages • Lake elevation • Seasonal patterns of natural river flow and lake level fluctuation • Response of the natural system to human influences • Water development plans • Groundwater

  8. Seasonal Flow Patterns

  9. Response of the natural system to human influences • To what extent have the base, high pulse, and overbank flows in the river changed over time in response to human influences? Have extreme low flows (i.e., subsistence flows) become more frequent or extreme? • What are the primary human influences on the flow regime, and where do these impacts occur? • What types of water development activities are planned for the future, and how might those developments influence river flows?

  10. Water Development

  11. Precipitation Watershed Boundary Headwaters Wetlands Floodplain Tributary Hillside Bankside Water Table Groundwater Connectivity/Hydraulics • Hydraulic modeling and flood hazard mapping • Relationships between river and lake stages • Relationships between river flow and hydraulic habitat. (i.e. distribution of velocities and depths in the river channel) • Longitudinal connectivity • Lateral connectivity

  12. Hydraulic Modeling / Wetland Inundation Mapping

  13. Watershed Protection Plan • Control of Caddo Lake levels • Ecosystem flows • Groundwater-Surface Water interaction • Flood protection and mapping • Drought • Capacity of Big Cypress Creek to handle releases from Lake O’ the Pines

  14. Topics for Breakout Sessions • Subsistence Flows • Little and Black Cypress Building Blocks and Research Priorities • Wetland Flood Plan Inundation • Groundwater – Surface Water Interactions

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