Logging Requirements:
Read the sign and look at the river banks.
1) What is the geological related function of this structure?
2) What would happen to you if you stayed here during the
1990s?
3) What can you see here along the banks that help to prevent
erosion?
Walk about 0.1 mile south along the trail to the walkway.
4) How does that area help to protect against flooding?
Go to the bridge over Roy Orr Blvd (N32 47.258 W 097 1.900) and
look west to river.
5) What modifications to the river can you see here that also helps
prevent flooding?
This earth cache is #9 on the Good Link Trail in Grand
Prairie.
Thanks to the Grand Prairie Parks Dpt for this trail and allowing
this earthcache.
The Trinity River has three principal branches:
the East Fork, the Elm Fork, and the West Fork. This is a stretch
of the West fork which comes from Fort Worth. It starts in Archer
county and flows 180 miles to meet up with the East fork and then
with the Elm fork to form the full Trinity river just west of
downtown Dallas. It finally ends up in the Gulf of Mexico east of
Houston. The Trinity is the longest river which is entirely
contained within Texas and half of the population of Texas lives
within its watershed. It was an important mode of transportation
for the Caddo Indians here and the Daycoa Indians near the coast
prior to settlement by Europeans. Today the Trinity and its lakes
and reservoirs provide scenic picnic, boating, fishing and
recreational activities.
Trinity River WaterShed
The average annual rain fall is 30 – 40 inches up here and
40 -50 inches around the lower part, but that is highly variable.
Rapid surface runoff during intense thunderstorm activity
frequently produces flash floods on the smaller tributaries and
upper reaches of the river. If the water does not flow fast enough
in the river it willspill out over its banks and cause major
flooding. Urban flooding is controlled through several methods as
described below.
Channelization is a series of large, straight
and empty (except when a flood is actually present) open-air
channels that extend below the street levels of some cities, so
that if and when a flood occurs the flood will run into the
channels, and is drained from the area. The removal of obstructions
from and the protection of the embankments along a river bed
furnish a simple and efficient means of increasing the flow rate of
its channel which will lower the height of floods upstream.
Upstream of a city natural floodplains and winding courses are
kept, so that floodwater is held back and released more slowly into
the river.
A wetland is an area of land whose soil is
saturated with moisture either permanently or seasonally. Such
areas may also be covered partially or completely by shallow pools
of water. Wetlands serve as natural water purification system. They
help the environment through their ability to hold carbon (CO2) in
their plants, and through their ability to store and regulate the
flow of water which reduces flooding.
A dam is a barrier that holds water back and
generally serves the primary purpose of retaining water. They can
provide drinking water, recreation and generally prevent water flow
into specific land areas which prevents flooding.
The Trinity River flooding in West Dallas on
8 July 1908
Current river level data is available at the
RIVER LEVEL hyperlink from the National Weather Service. This
hyperlinked program titled Water to the
Sea is an excellent online educational experience on all
aspects of the Trinity River produced by the Center for Global
Environmental Education at Hamline University. The information in
this Earthcache was found in The
Handbook of Texas Online, the Wikipedia page on River
Engineering and various other sources.
