Ecosystem Flows Hydrology and Connectivity Joe Trungale October 2, 2006

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

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

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

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC Instream Flow Building Blocks Big Cypress Creek/ Caddo Lake Low Flows High Flow Pulses Floods 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 6,000 cfs for 2-3 days Every 2 years * For channel maintenance Key Dry Year Avg Year Wet Year 90 cfs Fish habitat 218 – 49 cfs Spawning habitat cfs Maintain aquatic diversity cfs Fish habitat cfs Pre-dam median cfs Benthic drift & dispersal, fish spawning cfs Fish habitat cfs Pre-dam median 40 – 536 cfs Maintain biodiversity and connectivity (backwater & oxbows) 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)

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC Lake Level Building Blocks Caddo Lake Low Lake Level Normal Lake Level Elevated Lake Level Inhibition of upland vegetation Summer draw down to prepare for nutrient flush. Duration: every year for 1 ten year period Refill for Nutrient and sediment flush Duration: about 15 days This chart is based on the assumption that the lake would benefit from nutrient flushing. Unknowns 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

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

Seasonal Flow Patterns

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? 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 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? What types of water development activities are planned for the future, and how might those developments influence river flows?

Water Development

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

Hydraulic Modeling / Wetland Inundation Mapping

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

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