Eutrophication Studies

Environmental Compliance

Challenges with Eutrophication Studies

The US Environmental Protection Agency (EPA) describes nutrient pollution as “one of America’s most widespread, costly and challenging environmental problems.” This issue is of significant concern world-wide, with considerable resources now being committed in Asia and Europe to study eutrophication in streams, rivers, lakes, bays and coastal waters and related economic, environmental and human health issues.

Solutions Provided by EEMS

EEMS has powerful water quality simulation and analysis features. EFDC+ includes a complete eutrophication water quality module with unlimited phytoplankton and zooplankton groups, allowing enormous flexibility and control for a detailed description of the water ecosystem. It also includes a full sediment diagenesis model, allowing the simulation of long-term changes in water quality conditions in response to changes in nutrient loading by sediment fluxes released from the bed. EFDC+’s generic Rooted Aquatic Plant and Epiphyte Algae Sub-Model (RPEM), solves kinetic mass balance equations for rooted plant shoots, roots, and epiphyte algae growing on the shoots, helping improve the accuracy of water quality models.

EEMS is regularly used to simulate the growth and decay of algae and its impact on dissolved oxygen, as well as phosphorus and nitrogen cycles. The WQ sub-model is internally coupled with the hydrodynamics and sediment transport sub-model to allow the smooth exchange of constituents with the atmosphere and the sediment bed.

The post-processing options for eutrophication include 2-D plan (by layer or depth averaged), vertical section plots, and a range of animations. Unlike similar tools such as MIKE or DELFT, EEMS has all the tools available in one fully equipped package.

Examples of Studies Done with EEMS

Typical examples of water quality studies include:

Other Examples of Studies Done with EFDC:

Tenkiller Ferry Lake WQ Study, OK/IL, USA

DSI developed a linked watershed, hydrodynamic and water quality model of a portion of the Illinois Basin as part of development of a TMDL for Tenkiller Ferry Lake, OK. The Lake is identified as impaired because of elevated nutrients, and it is a high-priority target for TMDL development. The HSPF watershed model was used to simulate watershed runoff and point and nonpoint source loads from the watershed. The HSPF model was recalibrated to a 20 year simulation period. The HSPF provided flow, total phosphorus, total nitrogen and organic material loads. These HSPF results were then linked to the 3D EFDC+ water quality model flow of Lake Tenkiller. A two year simulation period was used for calibration of the EFDC water quality model. The calibrated model was then used to conduct load reduction scenarios as part of the TMDL process.

Little Bow River Water Quality Model Development, Alberta, Canada

The Little Bow River watershed is located in the headwaters of the Oldman River Basin in the southern region of the Province of Alberta. The watershed supports a wide variety of natural resources, including forests, minerals, wildlife, and agricultural lands. To support flood mitigation work related to Highwood-Little Bow diversion system and Little Bow River, a model was developed as an assessment tool to evaluate the existing flow and water quality condition in the upper Little Bow River and potential impact of various flood related management plans. The Environmental Fluid Dynamics Code (EFDC) platform was selected for the Little Bow River system.

Caloosahatchee River Basin Hydrologic, Hydrodynamic and WQ Modeling, FL, USA

The Caloosahatchee River Basin , extending from Lake Okeechobee to San Carlos Bay on Florida’s west coast, has several Waterbody Identification units (WBIDs) included in the State of Florida’s 2004 list of impaired water bodies because of nutrient enrichment and low levels of dissolved oxygen. The tidal estuary of the Caloosahatchee River is characterized by freshwater inflow from Lake Okeechobee along the non-tidal portion of the river that receives agricultural wastewater discharge and run-off from the urbanized and developing areas around Ft Myers. As part of FDEP’s TMDL development process, DSI/Dynamic Solutions, LLC developed a linked HSPF watershed and EFDC hydrodynamic/water quality model of the 1,400 square mile Caloosahatchee watershed, river and estuary.

The images below demonstrate EE visualizations of WQ parameters from the TMDL study of Caloosahatchee Estuary, Florida. The plan view animation displays the depth averaged DO values as algal blooms form in the estuary. A track through the model domain has been defined by the user and a profile animation along that path shows chlorophyll a formation near the surface later in the same year.

Download Example EE Models

Download an example model and run with the free EEMS Demo Version.

This model has been developed to demonstrate water quality and zooplankton simulation of Lake Thonotosassa. This model may be used as a guide to build other WQ models and can be loaded and run in the free demo mode of EEMS.

This model is provided as a useful exercise in how to build hydrodynamic model, and from that a water quality model, using available data, which is provided in the “Data” folder of this download. The steps to do this are provided in the How-to-guides in the EE Knowledge Base. The final models are also provided for comparison.