Evaluating Water Quality Upstream and Downstream from a Proposed Restoration Project on the Pomme de Terre River in Morris, MN

The recent push to restore natural river conditions provides opportunities to investigate the effects of dam removal and channel modification, particularly if data are collected before such projects are initiated. The MN DNR plans to modify the Pomme de Terre River channel at the Crissy Lake dam (Morris, MN) by constructing and directing water flow over stone arch rapids to remove the barrier to fish, restore flow, and enhance river conditions. We aim to characterize the Pomme de Terre River upstream and downstream from the project site before construction to provide data to compare with river conditions after the project is completed. We collected data bi-weekly from September–November at 3 sites upstream and 3 downstream from the Crissy Lake dam. We measured dissolved oxygen (DO), total dissolved solids (TDS), and Turbidity at each site. Average (range) values downstream were: DO 11.70 (7.36-17.53) mg/L, TDS 509.78 (469.20-:605.70) ppm, and Turbidity 2.70 (1.10-5.75) ntu. Average values upstream were: DO 12.54 (7.23-21.58) mg/L TDS of 476.79 (424.40-666.4) ppm, and Turbidity of 1.61 (0.55-4.00) ntu. DO levels suggest high levels of primary productivity and the capability of supporting aquatic life. TDS would be considered on the high-acceptable side of drinking water. Low turbidity levels show no indication of water quality impairment and reflect base flow conditions and lack of erosion in the absence of significant precipitation during the study period.