DO Improvement Feasibility Study
East Branch DuPage River 7.0 Evaluation
DRSCW 7-1 August 2008
7 EVALUATION
Based on the data collected and with the insight from the screening phase, a detailed evaluation
of alternatives for the dissolved oxygen problems on the East Branch was performed. Figure 7-1
presents the DO modeling results with the Churchill Woods Dam removed, under the same
condition as described in Section 4. The model predicts much improved DO levels above the
Churchill Woods Dam; however, minimum DO levels less than 5.0 mg/L are still predicted. The
DO levels at the Prentiss Creek Dam are predicted to remain above 5.0 mg/L.
Based on the continuous stream DO monitoring, we know DO values less than 5.0 mg/L occur
downstream the Churchill Woods Dam (at Hidden Lake). However, the sediment above the
Churchill Woods dam is the largest DO sink, and efforts to improve the overall stream DO
should initially focus at the Churchill Woods Dam. Once removed, then additional monitoring
(and perhaps modeling) would be appropriate before proceeding with any additional projects
designed to improve stream DO levels.
7.1 Evaluation Criteria
Criteria were developed to evaluate and compare the final set of alternatives on the basis of
benefits, impacts, and costs. These evaluation criteria will guide the identification and selection
of the preferred alternative. A set of evaluation criteria fact sheets were developed which
included a description of the criteria, the target, and the evaluation methodology. These criteria
are summarized in Table 7-1.
Table 7-1 - Alternative Evaluation Criteria
Ecological
Evaluations
Impact on Wetlands
Water quality
Impact on significant
Habitat
Impact on local ecology
& biological community
Physical
Evaluations
Sediment and
transport
Flood storage
Engineering
Evaluations
Site analysis
Channel stability
Permitting
Utilities
Flooding implications
Cost estimates
Scheduling
Implementation
Constructability
Operation &
maintenance
Sediment
characterization
Socio-economic
Evaluations
Land ownership
Land value
Noise impacts
Historical context
Community values
Recreation impacts
Change in Aesthetics
Safety issues related to
dams and aeration
equipment
