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Project description
One of the central responsibilities of the District is to maintain the balance between the water needs of current and future residents, while protecting and maintaining the natural systems which provide the area with its existing and future water supply.
In keeping with this mission, the primary goals of the Myakka River Watershed Initiative are as follows:
- Define current conditions of the watershed with respect to the District’s four areas of responsibility (flood protection, water supply, water quality and natural systems)
- Evaluate and illustrate the effects of potential future land use changes
- Develop and evaluate structural and non-structural best management practices (BMPs) that will support:
- Natural systems restoration (e.g., Flatford Swamp)
- Alternative water supply development
- Water quality improvements
- Flood protection
- Develop floodplain information suitable for FEMA Flood Insurance Rate Map (FIRM) updates
In order to achieve these goals, a series of models (surface water, water budget and water quality) will be developed and used to measure the effectiveness of the recommended strategies and goals to reach the desired watershed condition. The models must be developed in accordance with District guidelines and specifications and must stand up to public scrutiny.
Although the project encompasses the entire Myakka River watershed, the District has directed that priority be given to the development of the water budget for the upper Myakka area and evaluation of the Flatford Swamp sub-basin. This includes the development of restoration alternative for the Flatford Swamp area. The upper Myakka River watershed is defined as all contributing areas from Sarasota gage, located at State Road 72, to headwaters upstream.
Major elements of the initiative
The project includes the following primary elements of the District’s Watershed Management Program.
Digital topographic information
This element primarily involves review and merging of the existing digital topographic information, datum conversions, identification of topographic data voids and generation of the terrain geodatabase.
Upper Myakka water budget
This project element involves conducting surface water resource assessment activities in the upper Myakka region of the watershed. Typically this work is conducted as part of the Watershed Management Plan element but the task is scheduled earlier to address ongoing environmental concerns in the upper reaches. This task includes all activities necessary for the development and calibration of a continuous simulation model, evaluation of the impacts of land use changes and historical activities in the watershed, and the development of restoration alternatives.
Watershed evaluation
The watershed evaluation element is the systematic inventory and assessment of the water resource features of the watershed. It includes the following primary tasks:
- Collection and review of available information
- Delineation of sub-basins and development of the junction-reach network based on the available information
- Field reconnaissance (includes identification of maintenance requirements)
- Generic parameterization of hydrology and hydraulics features
- Surveys and field measurements
- Surface water resource assessment inventory and approach (includes water budget and water quality elements)
- Assembly of the above information into a spatial database
Note: At the start of this element, the Flatford Swamp sub-basin will be separated and the evaluation accelerated on a parallel path with the remainder of the watershed.
Watershed management plan
This element involves refining the information collected and developed under the watershed evaluation element and the development of a series of models for use in formulating planning and management decisions. These include a continuous simulation water budget model (for the remainder of watershed), a surface water model (for floodplain mapping and flood evaluation purposes), and a water quality model. The models will then be used to evaluate current conditions, develop solutions to watershed issues (flooding, water quality, ecological, water supply, etc.). Note that while floodplains will be delineated, the formal mapping of floodplains for submittal to FEMA is not included in the scope of the initiative.
Independent quality assurance (QA) review of program elements
There are three watershed studies (Howard Creek, Lower Myakka and Big Slough) within the Myakka River watershed that have been completed or are near completion. Only one is reported to have been conducted to current District guidelines and specifications. This element involves the review of each of these studies for errors and accuracy as well as compliance with District guidelines and specifications. The reviews will address all work that must be conducted to update, correct and bring the models in compliance with District requirements. Conclusions of the QA reviews will be addressed under the watershed evaluation and/or watershed management plan elements of the project.
