Estimating Reservoir Water Storage Capacity

Estimating Reservoir Water Storage Capacity


Sean Kimbrel – As sediment accumulates in
a reservoir, the capacity of that reservoir decreases. To meet various demands and beneficial uses,
such as for water supply, and hydropower generation Paul Boyd – Reservoir sedimentation is a
chronic issue. It will affect all reservoirs sooner or later. It’s simply a matter of time. In some cases, that may be a few decades. In some cases, it may be hundreds or thousands
of years. Dr. Tim Randle – Sedimentation is affecting
the project benefits for the nation’s reservoirs. It’s by filling up these reservoirs gradually,
over time, reducing the storage capacity, impairing outlets, impairing boat ramps, marinas,
impairing space for recreation, and we need to look at ways to better manage sediment
over the future more sustainably. Paul Boyd – The sedimentation rate that we
see in the reservoirs is driven by one: the weather patterns, two: the geography associated
with that reservoir. When we have reservoirs in areas that have
high rainfall, steep mountain valleys, a high amount of sediment available to come run off
the watershed… all of those things contribute to high loads that can result in accelerated
loss of storage volume. Sean Kimbrel – Current methods to measure
a reservoir’s sedimentation are done in two ways. The first is direct measurements, where you
have a boat with a depth sounder and GPS mounted to it to map the bottom of the reservoir,
and then you compare that map that you’ve created to an older survey. The second way to measure reservoir sedimentation
is indirectly where you’re using modeling techniques, whether it’s an empirical type
of model, or an analytical, or even physically based model to indirectly estimate the amount
of sediment accumulation in a reservoir. Tim Randle – One of the biggest limitations
is just our capacity to do it. There’s three hundred and some reservoirs
in Reclamation’s inventory… many more when you look at the full federal sector,
and private as well, and there just haven’t been that many surveys largely due to cost. Paul Boyd – These traditional methods require personnel on the ground to do that, and to
get to these remote areas, and as budgets are limited, we try to be the best stewards
of the resources we can. We have to make tradeoffs. For indirect methods, the limitations are
simply that our estimate is based on the quality of the data that’s available to either do
numerical modeling or watershed runoff estimates. Sean Kimbrel – So what we’re looking for,
in terms of an improvement, and the indirect estimates of reservoir sedimentation volume
is certainly perhaps a model or a method that is relatively more accurate, and less time
consuming for us to be able to estimate the accumulation of sediment in unsurveyed reservoirs. Tim Randle – And so if we can come up with
less expensive ways of doing the survey, or estimating, in lieu of the surveys, what that
sedimentation rate might be, that would be quite helpful for water resource managers:
knowing how much water is actually being stored in the reservoir. Paul Boyd – The prize challenge allows us
to query literally hundreds of millions of people to come up with good ideas. Tim Randle – The exciting thing for me about
a prize challenge is you get lots of people involved. There’s always somebody out there with a
wonderful idea, and they just need to be asked to give some time to think about it. It’s an opportunity to adopt that idea,
give that person some credit, and maybe some cash money. Paul Boyd – So, we’re partnering with
Reclamation because we both have the same needs; we both have data gaps that we’d
like to assess because we both feel that it’s very important to establish where we are right
now… look at our resource availability, and then look into the future and say, “What’s
going to happen to that resource? Will we be able to provide benefits in the
future, and if not, what action can we take now to preserve those benefits in the future?”

2 thoughts on “Estimating Reservoir Water Storage Capacity

Leave a Reply

Your email address will not be published. Required fields are marked *