Estimation of Inputs to Florida Bay

prepared for

U.S. Army Corps of Engineers  &  U.S. Department of the Interior


William W. Walker, Jr., Ph.D., Environmental Engineer

July 1998

Introduction  |  Methods  |  Report Sections  |  ReferencesAppendices  |  Data Needs  | Related Links  |  E-Mail



This report describes the development of input flow and load data sets to drive a water quality model of Florida Bay being developed by the U.S. Army Corps of Engineers, Waterways Experiment Station (Dortch et al, 1997).  This site has been established to communicate interim results and facilitate project review.  Please provide comments to W.W. Walker.

The objective of the project is to develop estimates of flow and loads of nutrients and other water-quality consituents entering the region from the Florida mainland, Keys, and atmosphere. The spatial scale is reflected by the model domain shown below:

map_dom.gif (16842 bytes)

The project is being conducted in two phases.  In the first phase, preliminary estimates have been developed for sources in the following categories:

  • Inflows from Florida Mainland
  • Runoff from the Keys
  • Wastewater from the Keys
  • Atmospheric Deposition

Other potential sources (e.g., rookeries, inputs from the Flamingo Visitor Center) may exist but have been ignored in the initial estimates.

Inputs are estimated on a monthly time scale for the period from October 1986 through December 1997.   A number of potential refinements have been identified in the process of developing these estimates.   Depending upon results of model sensitivity testing, some or all of these refinements may be implemented in a second phase of the project.

Water quality components of interest include (Dortch et al, 1997):

  • Phosphorus (Dissolved Organic, Dissolved Inorganic, Particulate Organic, Particulate Inorganic)
  • Nitrogen (Dissolved Organic, Particulate Organic, Nitrate+Nitrate N, Ammonia N)
  • Carbon (Dissolved Organic, Particulate Organic)
  • Silica (Dissolved, Particulate Biogenic)
  • Calcium (Dissolved, Particulate)
  • Salinity
  • Suspended Solids (Total or Inorganic)
  • Chlorophyll-a
  • Alkalinity

Since this list is considerably longer and more detailed than the list of water quality components that are typically measured, numerous assumptions regarding concentration and/or speciation will have to be made in order to estimate loads.  These and other assumptions made in developing the input data sets will be clearly defined and software will be provided to generate flow and load time series for alternative sets of assumptions.


The following table summarizes general strategies used to estimate flows and loads for each source:

Source Estimation Methods
Mainland - Flows Water Budgets on ENP Subwatersheds
Mainland - Loads Mainland Flows x Marsh Concentrations Measured in Each ENP Basin
Keys - Runoff Rainfall x Runoff Coef., Related to Land Use (USEPA, 1993)
Keys - Runoff Loads  Runoff Volume x Assumed Runoff Conc, Related to Land Use (USEPA, 1993)
Keys - Wastewater Inventories Compiled by USEPA (1993)
Rainfall - Volume Regional Monitoring Data
Atmospheric Loads Regional Atmospheric Deposition Data (Hendry & Brezonik, 1981)

Report Sections:


Data Needs:

Some of the above information has already been requested from various people.


Send comments or questions to W. Walker via e-mail.  Send data files to the following anonymous FTP site:    Send reports or other printed material to:  W. Walker, 1127 Lowell Road, Concord  MA  01742.  Phone 978-369-4230.  Fax 978-369-4230.   Direct questions on the Bay water quality modeling effort to Mark Dortch.   Thanks.

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E-Mail - W.W. Walker

W.W.Walker Home Page      Updated:  03/30/02