Variability (Trend) Network
The Trend Network examines long-term changes in Florida’s ambient water quality. The network consists of 125 fixed stations
whose locations are based on Florida’s 52 U.S. Geological Survey drainage basins. The Department manages this network, along with
a complementary program called the Status Network. Data collected by both networks are used to develop
action plans to protect and restore our water resources.
The Trend Network is divided into surface water (SW) and ground water (GW) components.
In both the SW and GW Trend Networks, water samples are analyzed for a suite of
water quality indicators.
Surface Water Trend Network
The SW Trend Network consists of 76 fixed stations in streams, rivers, and canals. Most of the sites are located at the
lower end of a USGS drainage basin and are situated at or near a flow gauging station. These sites allow the Department to obtain
chemistry, discharge, and loading data at a point that reflects the watershed’s water quality. Some SW sites are located at or near the
state boundary with Alabama and Georgia. These stations measure the conditions of major streams entering Florida.
SW Trend sites are sampled each month by personnel working for the Department, the Water Management Districts (WMDs), and county
agencies. All samples are analyzed in the Department’s Central Laboratory.
Ground Water Trend Network
The GW Trend Network consists of 49 fixed stations
(25 unconfined aquifer wells, 22 confined aquifer wells, and 2 spring vents). These sites are located so that
each USGS drainage basin has a representative site for both the confined and unconfined aquifer systems, when both of these systems are
present in the basin.
As with the SW Network, GW Trend sites are sampled by the Department, the WMDs, and county agencies. The Department’s Central Laboratory
performs all sample analyses. Because the water chemistry in confined aquifers changes much more slowly than in unconfined aquifers, field
measurements are taken quarterly at confined sites and monthly at unconfined sites. Samples for laboratory analysis are collected quarterly
at all GW sites.
We are grateful to the citizens and the public & private
agencies that provide us access to sample for regional and statewide water