Between the Lines: Some ideas on Mighty Mo management

 Think you know how to prevent the severe flooding that occurred on the Missouri River this year?

The local Living River Group of the Sierra Club has some ideas. Ponder them and see what you think:

1. Lower Pool Levels: Currently only 6 percent of reservoir storage capacity is allotted exclusively for flood control with an additional 16 percent designated for annual flood control and multiple use.  Consequently, the Corps of Engineers targets the reservoirs to be 78 percent full in early March at the start if the spring run-off season.  The flood of 2011 demonstrates that this level is too high.

Climate change must be taken into account.  Climatic models predict more extreme weather events, including higher precipitation causing occasional unprecedented high basin runoff.  This includes runoff that might exceed the

 2011 projected 57.7 million acre feel (MAF).  Since periods of drought are also projected to be more intense the Corps will need to be allowed more flexibility in their application of adaptive management.  Adaptive management would allow the Corps to incorporate new information into an ever changing management plan.  Lower pools, unlike levees, have no construction or maintenance costs and would increase nesting sites for the endangered least tern, threatened piping plover and other shore birds and promote fish reproduction (see below).

2. Unbalance the Reservoirs:  Unbalancing means the three biggest reservoirs, Fort Peck, Garrison, and Oahe, are lowered and raised in an alternating annual sequence to improve fish spawning habitat and increase nutrients from inundated vegetation.  Lowering the water level in a reservoir provides increased vegetation-free shoreline for nesting shore birds.  Raising water level s inundates vegetation, thus providing habitat and nutrients for aquatic organisms and enhancing fish production.  Under the current management regime, with reservoirs starting the year nearly 80 percent full, there's often no choice but to simultaneously raise all three reservoir levels to capture spring run-off.  Lower pools should allow more opportunity to utilize this vital management tool to increase reproduction in both shore birds and reservoir fish.

3. Implement the Spring Rise:  Biologists have long advocated spring dam releases that mimic the Missouri's historic natural flows; a brief rise in March mimics snow melt and another in late May/early June simulates spring rain (bimodal spring rise).  These are vital for the survival and recovery of native fish such as the endangered pallid sturgeon.  Sturgeon evolved on the river and they appear to time their spawning and birth cycles with the spring rise.  In addition, the spring rise inundates vegetation on river islands, clearing the islands, promoting nesting sites for plovers and terns.  Yet, the spring rise has never been fully implemented.  It has the potential to contribute to flood prevention, letting a little extra water out of the reservoirs in the spring and allowing for a small increase in reservoir storage for excess basin runoff.

4. Reduce Navigation Support:  Lowering the pools means our reservoirs begin each year with less water.  During drought years water conservation will become a priority since water intakes may be compromised and reservoir recreational facilities will become relatively inaccessible.  Water conservation becomes a priority during years of drought, and under the current management plan a great quantity of water is wasted to support a nearly non-existent river barge industry.

The barge industry has been steadily dwindling.  It is all but non-existent above Kansas City.  Most of the barge traffic is localized in Missouri where run-off from lower tributaries may provide sufficient flows to support barges.  During droughts the Corps has reduced the navigation season to save water.  If the pools are lowered the navigation season above Kansas will be shortened even more.

Lowering the pools also requires sacrifices for upstream states, since less water will be available for hydropower, water supplies, and recreational access.  The negative effects for both upstream and downstream states are offset by enhanced flood control and ecosystem benefits.  This is a reasonable shared sacrifice with large rewards for all of the basin states. 

Navigation requires not only massive amounts of water, but also extensive and expensive maintenance of its channel.  The narrow channel must be widened to allow the river to spread out during floods.  Before repairs to the extensive channel damages caused by this year's flood are undertaken, the cost of repairs, especially in the low navigation stretches above Kansas City, should be evaluated.  These costs and the extent of barge traffic should be made public.

5. Reduce Levee Dependency:  In general, the Living River Group is opposed to building new levees.  They are expensive to build and maintain, frequently fail and promote a false sense of security that encourages floodplain development.  Unfortunately, they also constrict the rive r by narrowing the floodplain.  This causes higher water in areas without a levee and disconnects the river from its floodplain.  As levees are rebuilt they should, where possible, be reconstructed farther away from the river, increasing the size of the floodplain and allowing the flood waters to spread out.

6. Promote Buy-Outs and Floodway Easements:  The most certain way to prevent flood looses is to prevent developments in flood-prone areas.  It is in the public interest to have the government purchase flood prone developments, that is much less expensive than helping people rebuild and provides an opportunity to allow flood waters to spread out into a broader floodplain.  It also enhances public safety, wildlife production and recreation opportunities.  Perhaps of equal importance to buy-outs are floodway easements.  The Bird's Point-New Madrid Floodway on the Mississippi River mitigated flood damage along that river this year.  Floodways would require easements or buyouts.  With easements farmers could continue production of crops in dry years, but when there is a need to expand the flood plain their land would be inundated.

7. Improve Zoning:  New developments in areas that are flood prone should be discouraged.  Inundation potential can be calculated with computer models based on past floods.  Counties should implement setbacks based on data supplied by the Corps and other federal and state agencies.  These agencies should also assist counties to define reasonable setbacks.  The setbacks should not be measured simply in distance from the river, but rather on inundation probability models.  Counties should also consider erodibility as a setback factor.  Zoning would preserve wealth, promote safety, and contribute to wildlife production and recreation along the river.  It would also promote flexibility in the implementation of management practices by the Corps.

8. Study Watershed Land Use:  We support studies that promote an understanding of the additional causes, beyond precipitation, for increased runoff.  For example, the Corps should be able to estimate increases in runoff attributable to the conversion of native and pasture grasses as well as bottomland riparian vegetation to row crop and grain production.

Bookmark the permalink.

Leave a Reply

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

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>