WRESTLING WITH THE RAGES OF HUBBLE CREEK

JACKSON -- Past tinkering by man and continuing urbanization upstream have left Hubble Creek one of the most unstable water systems he has ever seen, a federal geologist said Tuesday.

Stabilizing the stream bed, installing detention storage dams and regulating stormwater runoff were the solutions provided by the geologist's partner, an engineer with the Natural Resources Conservation Service.

Geologist Rob Cheshier and engineer Harold Deckerd, both based in Columbia, have completed a study of the Hubble Creek watershed. Tuesday they discussed their findings and toured problem areas with members of the Hubble Creek Local Planning Committee.

The committee, composed mostly of farmers in the watershed along with county and Jackson representatives, is trying to devise a plan to wrestle the creek under control.

The committee formed in response to a request from the Cape Girardeau County Commission. In places, erosion jeopardizes track used by the St. Louis Iron Mountain & Southern Railway and also threatens to expose a Gordonville water district line.

But the committee members quickly realized they needed a plan that addresses the entire water system, said David Owen, a Jackson-based district conservationist for the NRCS.

The tour took the committee to County Road 228 south of Gordonville, where dramatic erosion can be viewed from a bridge over the creek. Cheshier said the bridge eventually will have to be replaced because it is being isolated by the widening stream.

But that's not the bad news. "Degradation is moving on up through the system," Cheshier said.

"This is all headed toward Jackson," Deckerd said.

Overfalls, places where a stream drops dramatically and erodes the bed, occur about every sixth-tenths of a mile in this section of Hubble Creek.

Cheshier says past attempts to straighten the stream have contributed to the instability because they have speeded up the flow of water between the banks, deepening the channel. Because streams maintain their ratio of depth to width, a deeper stream also becomes wider, he explained.

Cheshier said the length of the stream channel between Jackson and the Diversion Channel has shrunk by four miles since 1922.

The Diversion Channel itself is a primary source of instability for Hubble Creek, Cheshier says, because the channel was cut lower than Hubble Creek. When they were connected, Hubble naturally began seeking the same level, he said, cutting the channel deeper.

Development is the other source of problems for Hubble Creek. Development increases runoff because water-absorbing ground is replaced with concrete and roofs. But at least urbanization is a source of erosion and flooding that can be controlled.

"It's really critical how dense a development Jackson allows to occur," Deckerd said. He recommends lot sizes of at least one-third acre to try to minimize runoff.

Deckerd's recommendations are:

-- Installation of grade stabilization structures, a system of pilings that can eliminate 4-5 feet of drop at overfalls. Deckerd says two or three are needed immediately in the stream at an estimated cost of $150,000 each.

-- Installation of detention storage dams. These dams would have the most effect in mid- and lower-Hubble because they cannot be built above housing due to the flooding danger. The dams vary in size but would cost about $20,000 each. About 90 are needed, Deckerd estimates.

-- Assist local political bodies to develop and implement a stormwater management ordinance. The goal of the ordinance is to keep post-development runoff from exceeding pre-development runoff.

This would be achieved through the construction of detention basins.

Owen said the committee will consider the NRSC recommendations along with others before settling on a final plan he expects to be ready by mid-spring. Once a plan is in hand, the committee will begin pursuing funding sources, he said.