The portion of the Healy Drain to be infilled will be pre-screened by a qualified environmental professional to determine the presence of water and the possibility of fish. If it is determined that fish are present then a qualified fisheries biologist will conduct a fish removal/salvage. If it is determined that there is not sufficient water levels to support fish then dewatering of the drain will be completed as necessary. The drain will then be stripped and filled in with Granular B material.
All activities associated with the infilling of Healy Drain, including but not limited to erosion and sediment control measures will be in accordance with the plan filed with the Minster to fulfill the requirements of Section 10 of the BSTA and this Fisheries Plan.
5. CONSTRUCTION IMPACTS AND MITIGATION MEASURES
5.1
POTENTIAL IMPACTS TO FISH AND FISH HABITAT
Potential impacts to fish and fish habitat within the Healy Drain will be limited. During the 2010 field investigations it was noted that Healy Drain is unlikely to support a fish community, even during high flow periods. These initial investigations noted that no fish were captured or observed in the drain and that it did not connect directly to the Detroit River.
Potential land-based or water-based impacts may occur downstream of where the PAR crosses Healy Drain (where the infilling will begin) to the Detroit River if the drain is connected during high flows. If work is completed during a low flow period, direct impacts to fish and fish habitat are unlikely, however, potential impacts that may result from the proposed work include:
- Alteration of riparian vegetation by equipment access which may affect bank stability and expose soils;
- Increased erosion potential leading to the release of sediment and or change in sediment concentrations;
- Temporary and permanent change in habitat structure and cover, food supply, and nutrient concentrations as a result of the placement of materials; and
- Introduction of contaminants including deleterious substances (e.g., fuel, oil, etc.) into the watercourse through the use of industrial equipment and construction debris which may lead to changes in water chemistry and/or cause direct mortality to aquatic organisms.
Disturbances as a result of the infilling of Healy Drain are expected to be localized and if work is done in isolation of the rest of the drain, then no negative downstream effects are anticipated. Existing baseline conditions in the downstream section of the Healy Drain, as well as the Detroit River, including temperature, flow, and suspended sediment are not expected to change as a result of this work. To mitigate potential changes in baseline conditions downstream, all in-water work (infilling of Healy Drain) will be either completed in the dry or in isolation of the remaining downstream section of the drain.
5.2
RESIDUAL IMPACTS AND COMPENSATION
No residual impacts or serious harm to fish will occur within the Healy Drain and Detroit River, so long as mitigation measures and best management practices are implemented and function effectively. As a result of the analysis of existing conditions in the proposed portions of Healy Drain to be infilled, it has been documented that fish currently do not occupy this portion of the drain, and if present seasonally, they have little habitat dependence
A reach of approximately 420 m of Healy Drain, an approximate measure using aerial mapping, will be lost as a result of the infilling works. Any potential seasonal fish habitat that may be lost will be offset through the proposed improvements to the Broadway Drain as a result of the realignment and habitat enhancement design developed by Landmark Engineers Inc.