When Is It Safe To Wade?
That depends on the Experience, Knowledge and Judgement of the
individual and the Risk that person is willing to assume. The
general guideines apply:
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Flows above 550 cfs are unsafe to wade.
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Flows between 300 to 550 cfs should be undertaken by only those who have
experience wading swift water conditions. Preferrably, you will have knowledge
of the river bottom and would have waded the area previously. Much of the river
will still be too swift and too deep to wade safely. The potential for being
swept off your feet is high.
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Flows between 200 to 300 cfs can be undertaken by most experienced waders.
There are still areas that may be too swift or deep to wade. Inexperienced
waders will have to be aware.
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Flows below 200 cfs have moderate current. A few areas may create fall down
potential.
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Flows below 100 cfs have slow current.
Remember the Guadalupe is a fast flowing river. A fast current can carry you
away like a fly in molasses. Always be cautious and wise about the river and
its hazards.
What Are The Flows Going To Do?
If you are making plans to fish the Guadalupe, there is always going to be
uncertainty about how much water is going to be released from Canyon Dam. This
webpage gives you the tools to make an informed decision.
The most significant predictor for flows below Canyon Dam is the lake elevation
of Canyon Lake itself. Using the Canyon Lake Elevation link you can retrieve
'real time' lake elevations. If Canyon Lake elevation is:
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908.9 and below, the lake is in conservation pool. Releases are low.
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909.0 the release rate will match the greater: Spring Branch Gage, or 90 cfs.
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909.1 and above, the lake is in flood, heavy releases are imminent.
The Army Corps of Engineers controls the lake when it is in flood (above
elevation 909.0 msl). Generally, these are extemely swift, high volume
releases, and are determined by how high the lake is, downstream flooding, and
other factors. The Corps wants to return the lake to the conservation pool as
quickly as possible. Here are some approximate scenarios on how the Corps makes
flood control releases:
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Lake Elevation 911 and higher: Heavy releases of 5000 cfs.
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Between 910 and 911: Flows will vary between 1000 to 5000 cfs.
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Between 909 and 910, flows will range from 250 up to 2500 cfs.
As you can see, the only potential for wading while the lake is in flood is
between 909 and 910 elevation- and most of the time, flows are going to be too
swift to fish. The exception is when the Corps of Engineers grants a 'temporary
deviation' to their normal flood control release procedures. This will happen
between April and August when the Corps will release flood waters at a slower
rate to enhance recreation for the floaters below Canyon Dam. Flow rates will
generally be the greater of: The flow rate at Spring Branch Gage; or 250 cfs.
Below 909.0, The Guadalupe-Blanco River Authority controls the flow. The
minimum flow is 90 - 100 cfs, and can be lower during drought. The GRTU-GBRA
Flow Agreement provides trout protective flows from May 1 to September 30 in
non-drought years. These flows will average around 200 cfs for the time period.
Canyon Lake elevation is important to determining flows below Canyon Dam. For a
more complete picture, you'll need to review the trends. There are two stream
gages above Canyon Lake: The Comfort Gage and the Spring Branch Gage. If there
is high water or flooding at the Comfort Gage, it takes about 24 hours for the
water to reach the lake. The Spring Branch Gage gives you a good idea of how
much water is flowing into Canyon Lake. Generally, if Canyon Lake is between
909 and 910, the volume of release from Canyon Dam is going to be a little
higher than the flow at the Spring Branch Gage. It is also important to review
the recent history of these gages and Canyon Lake elevation itself. Patterns of
rising, or falling, can indicate what will happen. At 909, the outflow will
approximate the flow at the Spring Branch Gage.
There are also two stream gages and the Corps' own estimation of Canyon releases
below Canyon Dam. The Corps's estimate is based on the gate opening at the dam.
It is updated only twice a day. The two stream gages are updated about 6 times
a day. These give you informaton about what is happening on the river "real
time" and you should check those gages prior to leaving for the Guadalupe.
Often one or more stream gages are out of commission, that is why more than one
source of river flow is found here. The Sattler Gage is generally considered
the most accurate.
The geology of the Guadalupe River watershed is limestone formations that
collects rainfall into subteranium reservoirs that release the flow back into
the river from artesian springs months after the last significant rainfall.
After a period of heavy rains, high inflows into the lake will persist long
after the last raindrops have fallen. During the winter when the vegetation is
dormant and the air temperatures are low, high inflows will persist longer.
What this means is it can take a long time after the initial flood for the
River to be wadable again. When the lake is drawn down near the conservation
pool, the Corps and GBRA will match the inflow coming into Canyon Lake. That is
one reason why the Spring Branch Gage is so important in determining what flow
rates will be.
Call The Corps of Engineers
You can also call the Army Corps of Engineers recorded Canyon Lake Dam
information line at 830-964-3342
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