Home
   
Information  
   
Join  
   
News  
   
Library  
   
Topics  
   
Documents  
   
WRAC  
   
Links  
   
Site Map  
   
Water Column  
   
Aquatic
Nuisance
Species
 
   
Estero Bay
Nutrient
Management
Partnership
 
   
Watershed Open Golf Tournament  
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

 

LEE COUNTY WATER BUDGETING : A Primer 
Wayne Daltry,

 

1.  Standard Income

 

All standard income is from RAINFALL. 

Lee County gets on an annual average 52" rainfall a year.  In other words, 4 and 1/3 cubic feet of water land on every square foot of Lee County, and every cubic foot of water has about 7.5 gallons of water in it.   Each square foot of Lee County then gets approximately 32.5 gallons dropped on it each year.

Lee County is 804 square miles.  To calculate this rainfall volume in gallons, it is 804 times 640 times 43560 times 32.5.  This totals 728,462,592,000 gallons as income.  Convert this into million gallons a day and the number is 1,996 mgd.  Convert this into one equivalent stream flow as cubic feet per second, and the number is 3080 cfs.

 

2.  Transfers In

 

Lee County receives transfers “in.”  This is streamflow, piped water, and aquifer flow that come in from other counties.  The Caloosahatchee is the obvious flow “in” since it comes from one site.  There are other flows that come into the county from neighbors.

Aquifer flows from other places are pervasive.  They start as rainfall elsewhere and come in more slowly.

 

 

3.  Enterprise Income

 

Enterprise income is taking saltwater and converting it to freshwater.  Done naturally by sunlight through a distillation process, technology makes this source more reliable for use, whether reverse osmosis or more involved desalination.  It is in use in Lee County in three places.

 

 

4.  Standard Expenses

 

There is one standard expense: evapotranspiration.  This is the humidity.  The evaporation rate is an expense that can be tinkered with by creating more space to hold water so it can evaporate, or remove it too fast to evaporate, or quickly store it.  For a rough number, though, an expense of 80% is presumed.  Taking away evaporation applied at a constant rate, and the water available is 145692518400 gallons, or 399mgd, or 614 cfs.

This expense (plus transfers in) sustains our terrestrial ecology.

 

5.  Transfers Out

 

There are three types of transfers “out.”  They are drainage, water piped out, and aquifer flow out. 


Drainage is a normal condition and it occurs naturally when the storage (see savings account/cashbox) is full.  Drainage goes to other counties or into the saltwater system, which makes it a transfer into estuarine ecological productivity.  (However, variations in volume damage estuarine productivity)

Water piped out is not occurring to any great extent, but does happen in many Florida Counties.

Aquifer flow out is either a continuation of flow of an aquifer that underlays the county or one that originates in the county but continues on.

 

6.  Enterprise Expenditures.

 

This is the forced dehydration of our water storage areas (see savings account/cashbox). Whether called drainage or flood control, this removal of water-involving human expense-eliminates some portion of the water available from Lee County sources.  When Enterprise Expenditures and Transfers Out exceed the water left (“cashbox”) after standard expenses, then problems occur for man’s living allowance.

 

7.  Cash Box

 

The “cash box” is the water “transitioning” from “income” to “expense”-a surface water pond or reservoir, the water table aquifer (a.k.a. groundwater), or a river or stream.    We use it, and affect the nature of the transition, but it still transitions.  Under a natural system process, there is always water in the “cashbox,” just less at the end of the dry season than there is in the wet season.

 

8.  Savings Account

 

The savings account is the water “not transitioning.”  This would be water bodies that are always present.  This would be the lake level that never drops below a certain point, groundwater sources that never empty.  It is the rainfall that is never “consumed” and has built up over thousands of years.  For Lee County it would be the aquifer systems below the surficial/water table aquifer.  These may be in transfer in/out mode, but are there.

When our expenses exceed the cashbox, we draw from our savings.  If we do not replenish our savings, and keep drawing from them, we face bankruptcy.

 

9.  Bankruptcy and Foreclosure.

 

Bankruptcy begins with water shortages and ends with foreclosure through water sources polluted with salt, or dried wetlands/dead wildlife, or rural fires that rage beyond management.  We are facing some aspects of bankruptcy as an annual occurrence.

 

10.  Living Allowance

 

We do not consume water-we use it-utilities, farm irrigation, mining, and so forth.  How much we can use depends upon how well we balance income and expenses.

 

Wayne Daltry is currently serving as Lee County's Smart Growth Executive Director after retiring from a career as Executive Director of  the South Florida Regional Planning Council

 

      

  

 


 

 

This site designed and hosted by

Questions or problems regarding this web site should be directed to web@swfwc.org.
Copyright © 2005 Southwest Florida Watershed Council.  All rights reserved.
Last modified: Sunday January 27, 2008.

Click here for more information