Our three reservoirs are water supply reservoirs. We have no flood
control storage.
Once the reservoirs are full, and it rains on already full reservoirs, we
must release water and pass those inflows, in real-time, downstream by
opening gates. We have to mimic nature because if we don’t, the water level
will rise to a certain degree that could impact the integrity of the dams.
We have to release what comes in. We have protocols and procedures and
constraints related to that.
As far as the upper basin, the last three months were really dictated by the
rainfall that occurred on top of PK and on top of Granbury and upstream. We
had a lot of water that was sourced from upstream, and that’s why we had
prolonged releases in some instances. When it’s wet, we have to release
what comes in to manage the reservoir level and keep it at safe levels to
avoid having issues with the dam.
As it relates to water supply, when we get to dryer conditions like we are now,
we still have residual inflows, and we’re releasing more. At Possum Kingdom,
we’re releasing more than our FERC minimum flow requirements associated with
our water rights. Right now, it’s 75 cfs, but we’re actually releasing about
130 cfs. We have to look at downstream customer demands as far as the timing
and when and how much we release water during dry conditions.
As it relates to maintaining a 200 cfs release rate from Memorial Day, the end
of May, through Labor Day, we just can’t do that. If we’re in drought conditions,
we can’t release water just to release water because that would severely impact
the amount of (water supply) storage we have in our reservoirs, and it would
jeopardize the amount of water we could provide to our customers.
Once we get into dryer conditions, we have to conserve and impound the water
and then look downstream as far as to what our demands are in supplying (water)
to our customers.
It’s a balancing act.
For information on how releases are made from BRA dams, go
here.