Dingman Creek Environmental Assessment

An Environmental Assessment is the process of determining what environmental impacts, if any, there will be during a project and how to minimize the impacts. The Environmental Assessment process falls under the Ontario Environmental Assessment Act.

The term "environment" includes the natural, social, cultural, built and economic environments.

There are two types of Environmental Assessment (EA) processes:

1. Individual EA - where projects have Terms of Reference and an individual environmental assessment carried out and submitted to the Minister of the Environment for review and approval.
2. Class EA - where projects are approved subject to compliance with an approved class environmental assessment process with respect to a class of undertakings.

The Dingman Creek subwatershed covers a total of 17,200 hectares and is located in Middlesex County with 74% of the area within the City of London.

The Dingman Creek EA is the most important stormwater EA that will be completed by the City for over the next 15 years. The recommendations of the Dingman Creek EA are intended to mitigate the impact of future development on water resources and to remediate the subwatershed, with consideration for current and potential flooding, erosion concerns, as well as wildlife/aquatic habitat and natural corridor enhancement. The focus of the study will be providing stormwater management solutions to facilitate development in South London for lands within the Urban Growth Boundary for the next 20 years.

The concept of a “complete corridor” will also be evaluated as part of the EA process to promote the movement of stormwater, wildlife, and people. The recommended strategy is intended to be a showcase project for south London as well as a fiscally responsible approach to stormwater management in the subwatershed. This study also includes a Ministry of the Environment, Conservation and Parks (MECP) Pilot Project to streamline stormwater approvals and reduce future study costs.

The aim of the EA study will be to address the following Problem Statement:

“The Dingman Creek Subwatershed (DCS) suffers from poor water quality, a lack of wildlife habitat, loss of trees and vegetation, as well as flooding and erosion issues.

Sustainable growth within the Urban Growth Boundary of the DCS is a City of London priority. To maintain, enhance, and restore the DCS, the City needs a comprehensive plan to support both environmental and development goals. This Plan must:

• Build on the 1995 and 2005 Dingman Creek Subwatershed Studies and be consistent with the goals and objectives of the Official Plan and Southwest Area Secondary Plan;
• Meet the targets established in the Environmental Compliance Approval (ECA);
• Create a "complete corridor" that provides a continuous natural area for the movement of water, wildlife, and people.

Note: The Dingman Creek EA will not delay construction of approved Site Plans or Draft Approved subdivisions.”

UTRCA Floodplain Update

In parallel to the Dingman Creek EA, the UTRCA has undertaken a comprehensive review of the floodplain hazards within the Dingman Creek Subwatershed. The UTRCA Regulatory Floodplain Update is expected to have implications on the limits of the floodplain and as a result planning and development applications within the floodplain area determined through the update. A preliminary hazard lands 'screening area' for the Dingman Creek Subwatershed has been developed by UTRCA. This map is included in the November 12, 2018 City of London report to Planning and Environment Committee and identifies the ‘screening area’, where further review and refinement will continue as options for engineered flood mitigation and/or policy solutions are assessed through a subsequent phase of the Dingman EA. For more information regarding UTRCA's Flood and Erosion Hazard Mapping, visit their website at http://thamesriver.on.ca/planning-permits-maps/flood-erosion-hazard-mapping/.

EA Phasing

The objectives of the Dingman EA study are to develop stormwater servicing solutions for lands that are scheduled for development. As a result, the UTRCA floodplain update has triggered the recommendation for the EA to be phased into two components (See map for Stage 1 lands). Stage 1 will address stormwater servicing requirements for select lands under the original EA scope of work. Stage 1 will only recommend municipal infrastructure for new development within tributaries outside of the area of influence of the updated Dingman Creek hazard lands. Stage 2 will be a continuation of the Master Plan EA process but will include a new or expanded problem statement to analyze potential engineering infrastructure for Dingman Creek (and tributaries not included in Stage 1) to mitigate flooding on impacted lands (as well as to improve access), all in consideration of the updated hazard information. During this time, the UTRCA will continue to confirm the extents of the natural hazards that are components of the UTRCA’s Regulation Limits.

An overarching concept of the EA is to create a naturalized corridor within South London as part of the stormwater management strategy. As such, the study includes looking at the option of creating a “complete corridor” to convey water, wildlife and people.

The three components of the complete corridor include:

• The Dingman Creek – to convey water and provide habitat for aquatic life;
• The Floodplain Corridor – to consider expanded storage within the existing floodplain and connect significant Natural Heritage System features.
• A Pedestrian Pathway – to encourage physical activity, including walking, running, and cycling.

The complete corridor is intended to be a unique feature for South London with limits expected to be between Wonderland Road South and Wellington Road South.

The Dingman Wetland is an example of how the complete corridor could look when implemented. The Dingman Wetland was constructed by the City of London in 2015 and incorporates expanded water storage within the existing floodplain for erosion control while creating enhanced wildlife habitat and restoring natural heritage features. The Dingman Wetland is approximately 18 ha in area (equivalent to 114 NHL hockey rink ice surfaces) and provides 210,000 m3 of water storage (equivalent to volume of 84 Olympic size swimming pools) for erosion control. Over 1.8 km of new fish habitat was created through this project and is supplemented by other habitat features including 15 bird houses, 7 bat houses, 5 turtle nesting islands and 16 floating basking logs. The Dingman Wetland is currently utilized by diverse wild life including migrating birds, geese, butterflies and the American Mink. The Dingman Wetland is designed to be periodically flooded during storm events but is not intended to be a permanent water body. The bottom of the Dingman Wetland is designed to be a shallow marsh or meadow marsh habitat for most of the year.