Domestic Self-Supply and Private Landscape Irrigation Wells Richard L Marella and Darbi R Berry U.S. Geological Survey Florida Water Science Center & Stacie Greco Alachua County Environmental Protection Department February 2016
Domestic Self-Supplied Users Typically residential households that rely on a privately owned well to supply water needs. Exclusively groundwater in Florida. Wells are normally 4 inches or less in diameter and do not require a consumptive use permit (CUP) from the Water Management Districts (WMD). Many local Health Departments do permit and track the installation of these wells.
Domestic Self-Supplied Water-Use Water-use is estimated based on a per capita use for the population not served by public supply. Per capita ranged from 80 and 105 gallons per day (gal/d) for calculating domestic self supplied use for most counties in Florida for 2012. 2.25 million Floridians were assumed to be selfsupplied in 2012 with a calculated water withdrawal of 210 Mgal/d.
Domestic Self-Supplied Water-Use Number of wells is unknown and is believed to be high in many areas (Hillsborough, Marion, Palm Beach) We estimate there are 750,000 and 800,000 domestic self supply wells in Florida. Statewide water-use would equal about 275 gallons per day or about 100,000 gallons per year per well. The amount of water actually used may be low because per capita use may be under estimated. A non-funded pilot study in Alachua County indicates a wide range in measured per capita (from 60 to nearly 350 Gal/d)
Domestic Self-Supplied Metering Pilot Goals Project in Alachua County Develop a cost effective method for estimating domestic self-supply water use Compare estimated per capita water use to metered water use data Demonstrate seasonality Started with 12 sites in 2012. Down to 8 sites in 2015.
Equipment Digital Time Totalizers (DTT)- minimally evasive way to monitor water use Inductive- a logger that records the time and duration that electricity is running to the well pump Vibration- a logger that records the time and duration that the pump is running based on vibration
Equipment In-line flow meters- Sensus iperl Donated by Gainesville Regional Utilities to verify digital time totalizers & to help calculate flow rates Installation funded by a small St. Johns River Water Mangement District cost share agreement
Methods Volunteers were recruited by Alachua County Environmental Protection (not a random sample). DTTs were installed on 12 domestic wells. In-line meters were installed on 3 domestic wells in tandem with the DTTs. 2 wells had in-line meters previously installed by the homeowners, for a total of 5 wells with dual meters. Data was downloaded quarterly (sometimes monthly) using a laptop computer and HOBO software. Flow rates were estimated at some sites.
What we have learned Domestic self-supply water use varies greatly between users, especially with outdoor uses. Use of irrigation systems appears to drive the variability between the high and lower water users. Patterns in water use (leaks, vacation, outdoor needs) are reflected in the limited data set. Domestic wells can be metered effectively.
Annual volume per site and relative per capita use (June 2013- June 2014) 250,000 400 Annual water use volume (gallons) 200,000 150,000 100,000 50,000 350 300 250 200 150 100 50 Annual per capita (gallons per day) 0 1 4 6 7 9 Statewide Average Site Number 0 Volume in Gallons Per Capita
900 Rainfall vs. Monthly Water Use (June 2013-May 2015) 18 800 16 Monthly Average Use (gallons per day) 700 600 500 400 300 200 14 12 10 8 6 4 100 2 0 0 Jun-13 Jul-13 Aug-13 Sep-13 Oct-13 Nov-13 Dec-13 Jan-14 Feb-14 Mar-14 Apr-14 May-14 Jun-14 Jul-14 Aug-14 Sep-14 Oct-14 Nov-14 Dec-14 Jan-15 Feb-15 Mar-15 Apr-15 May-15 Rainfall (inches) Site #4 Site #7 Monthly Rainfall
Challenges Data must be downloaded monthly, bi-monthly, or quarterly to eliminate data gaps. Obtaining flow measurements for some sites is difficult. Identifying willing participants is often challenging.
Needs Staff time to recruit additional volunteers (minimum of 30 wells). Staff time to download data. Database for storing and analyzing monthly data. Specialized equipment needed for calculating flow for each well. Additional DTT meters and In-line meters In-line meters require a licensed plumber for installation.
Private Landscape Irrigation Wells Typically households with a public water source for their indoor needs with an on-site water source solely used for landscape irrigation. Groundwater or Surface water mostly wells, but in some areas canals, ponds, or lakes. Wells are normally 4 inches or less in diameter and do not need a CUP from the WMD, however, these wells are usually managed by a local Health Department.
Private Landscape Irrigation Users Number of wells/surface water intakes is unknown. In many counties it is believed to be high. Increased water rates by utilities over the past 20 years entices homeowners to install irrigation wells to off-set high water bills. Many home owners believe their wells are exempt from irrigation restrictions. This water-use decreases public supply withdrawals, thus lowering per capita estimates. Utilities are losing revenue however, this often enables many utilities to stay under CUP withdrawal limits.
$4.00 Utility Water Rates for Selected Utilities $3.50 $3.00 Price per 1,000 Gallons $2.50 $2.00 $1.50 $1.00 $0.50 $0.00 1979 1989 1999 2006 2009 2012 2015 Sarasota County City of Sarasota Manatee County City of Bradenton
Irrigation-Landscape Well Permit Applications Issued in Selected Counties 1400 1200 Number of issued permits 1000 800 600 400 200 0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 HILLSBOROUGH MANATEE SARASOTA
Private landscape irrigation users in Florida - Challenges and Issues Number of wells being used for landscape irrigation is very difficult to obtain and assess. Very little, if any, data exist on the amount of water used by these wells. In high density areas, withdrawals may have a significant impact on the local resource. This landscape irrigation water-user directly impacts public supply withdrawals and calculated per capita values.
400 Manatee County 400 Per capita (mgd) 350 300 250 200 150 100 50 350 300 250 200 150 100 50 Number of Well Applications Issued 0 0 Irrigation-Landscape Well permit applications Issued Per Capita
Domestic self-supplied and private landscape irrigation users in Florida What is next Develop a statistically valid regional voluntary metering program to verify domestic per capita use and lawn irrigation volumes. Identify the number of irrigation wells to analyze the effect on public supply per capita. Better documentation and consistency of permit applications among agencies.
http://fl.water.usgs.gov www.alachuacountywater.org