Repository: UIHistories Project: Board of Trustees Minutes - 1976 [PAGE 178]

EXTRACTED TEXT FROM PAGE:

1975]

UNIVERSITY OF ILLINOIS

167

T h e Harza Engineering Company has concluded that the potential impacts of the Springer Lake Project are not "greatly changed" from those perceived and accepted at the time of the signing of the 1970 Memorandum of Agreement. T h e problems perceived and accepted are no worse and may, in fact, not be as serious as thought at that time. The changes in the physical environment of AUerton Park that will result from construction and operation of the Project as presently proposed in the draft Environmental Statement, September 1973, " W I L L BE M I N O R AND W I L L N O T R E S U L T I N S I G N I F I C A N T CHANGES I N T H E E C O L O G Y OF T H E PARK." Dr. Charles Kendeigh, Professor Emeritus of Zoology and formerly Chairman of the Committee on Natural Areas, believes that the magnitude of the "increased flooding and its adverse effects upon the ecology of AUerton Park is significant." There is a continuing professional difference of opinion concerning the quantitative and qualitative differences in "what is significantly increased flooding" and what constitutes adverse effects upon the ecology of AUerton Park. Dr. Kendeigh expresses his view and those of a number of scientists who have used, are using, and will in the future use Allerton Park for educational and research purposes. Their objectives are to preserve, unchanged by the project, the natural resource of Robert Allerton Park. A review of the draft Environmental Impact Statement and the P R E L I M INARY Updated Final Environmental Statement, prepared by the Chicago District Corps of Engineers, August 1974, an advanced copy of which was received by the University on January 6, 1975, does establish the fact that in Allerton Park the project will cause: 1. Overbani Hooding in the floodplain that will occur more frequently, with greater depth and with longer duration than now exists without the Springer Lake Project. 2. T h e project will modify the natural flooding pattern near the downstream boundary of Allerton Park for specific Hood events. 3. Within the Sangamon River channel, within the boundaries of AUerton Park a 623' msl joint-use (conservation) pool elevation will cause a "ponding" effect that will change the natural ecological conditions of a flowing stream in Allerton Park. 4. There may be increased siltation within the park and a higher water table may result from the Lake Springer Project. T h e area affected within Allerton Park is considered by the Corps and by the Harza report to be relatively small and insignificant. Groundwater studies and vegetative studies conducted by the Springer-Sangamon Environmental Research Project (SSERP) have concluded that quantitatively the effects upon vegetation in Allerton Park will be minor in the bottomlands. It is up high upon the bluffs in a zone of fifty-five acres that infrequent ( 5 0 100 year probability) and short duration flood events may damage vegetation that has never been subjected to flooding. T h e operational plan must take this fact into consideration by managing flood levels and release rates to avoid prolonged flooding at high elevations within Allerton Park in the zone indicated on the attached map. 1 These changes, caused by man-made flooding will eventually change the "natural" habitat of Allerton Park. There will be no clearing of timber or other vegetation (3' above the conservation pool elevation to 626' msl) within the boundaries of Allerton Park. The limits of clearing outside of Allerton Park will be approximately a half mile to the southwest of the southwestern boundary of Allerton Park. T h e effects of the joint-use pool upon the vegetation above 626' and into the

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A copy of this map is filed with the Secretary of the Board.