| The John
F. Kennedy Space Center in Florida is the home of NASA's
space operations. Located within the
Indian River Lagoon watershed, it is the largest public land
area along Florida's Atlantic Coast. Much of it has been turned
into the Meritt Island National
Wildlife Refuge.
While continuing its space operations NASA strives to protect the
environment and the threatened
and endangered species living in it. That is why it commissioned
a study to evaluate the effects of land-use changes on water run-off
in the Indian River Lagoon and the Kennedy Space Center.
The study used the Long-Term
Hydrologic Impact Analysis (L-THIA) tool to analyze information
for the time period between 1920 and 1990.
The results showed that changes in estimated run-off depths for
peak rainfall events - which are traditionally used to calibrate
water treatment infrastructure design - ranged from about 7-17%
for the Kennedy Space Center to 22-55% for the Indian River Lagoon.
Estimated average annual run-off for the Kennedy Space Center increased
about 49%, while run-off for the Indian River Lagoon increased nearly
113%.
The striking differences in run-off changes are due to differences
in rates of land-use change. For both areas most of the increase
came from urbanization
of the landscape. The Indian River Lagoon has experienced far
greater urbanization than the Kennedy Space Center and also greater
agricultural development.
The study demonstrated that estimated changes in run-off, which
are based only on peak rainfall events, can greatly underestimate
the overall impacts of land use on the quality and quantity of water.
Therefore, the effects of land-use alteration on annual or long-term
run-off should be considered in land-use planning. The GIS
version of L-THIA is a simple tool for determining changes in
average annual run-off using readily available data. |
Case
Studies