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� . . � � Appendix I <br /> be determined based on the estimated wetted perimeter of channel reaches computed for <br /> the expected level of pumpage, multiplied by the length of the selected reaches. <br /> Data collected from the stream gaging stations at the well field and at Highway 47 will <br /> be used to check the results of the seepage calculations. <br /> Subtask B.2 - Effects of Groundwater Conveyance on Existing Uses <br /> The use of Friends Creek as a conveyance for groundwater during periods of low natural <br /> flow may have a positive impact upon its suitability for aquatic habitat. To examine this <br /> possibility Harza will look at differences in wetted area and average flow velocity during <br /> oundwater co ve a ce u conditions as develo ed in Subtask B.1. <br /> gr n y n and nder existmg , p <br /> These parameters provide a simple measure of aquatic habitat and will be applied for <br /> conditions with and without the project to assess the degree of improvement or <br /> degradation of habitat likely to result from channeling groundwater through the stream. <br /> Also included in this subtask will be an assessment of the degree to which these flows <br /> may accelerate streambank erosion. <br /> As well as investigating the effects of rises in stream level on aquatic habitat, this <br /> subtask will also assess whether elevated stream levels may harm adjacent riparian <br /> lands, in particular riparian farm lands. Should estimates of water levels indicate that <br /> stream levels may submerge drainage outlets, Harza will discuss feasible mitigation <br /> options with local soil and water conservation districts. <br /> Subtask B.3 - Technical Input to Legal Assessments <br /> Should it be determined that seepage and evaporation losses expected from conveying <br /> water via Friends Creek and the Sangamon River are within acceptable limits, the <br /> question will remain as to Decatur's legal standing to reserve water pumped in the river <br /> for its own use. The Harza team will provide technical e�ertise to the Client's legal <br /> staff to assist them in anticipating and evaluating potential legal obstacles. If Friends <br /> Creek were used to convey groundwater during droughts, Harza recognize that owners <br /> of riparian land may seize this opportunity to divert a portion of this water for purposes <br /> such as irrigation. Harza will provide technical assistance to attorneys representing <br /> Decatur so that they can determine to what degree Illinois law may protect the Client <br /> from such diversions. <br /> If it appears that Decatur's legal protection from significant diversion of ground water <br /> would be insufficient, Harza will then assist in assessing economic options available to <br /> the Client, specifically the costs of contracting with potential users to forego diversion of <br /> water from Friends Creek during periods of groundwater pumping. <br /> a9iois <br /> A893092N-APP.I I-3 � <br />