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HomeMy WebLinkAboutDTS-06-041 - Voisin Greenway Rehabilitation Environmental Assessment ) R Development & Technical Services Report To: Chair and Members Development and Technical Services Committee March 27, 2006 Date of Meeting: Submitted By: Prepared By: Ward(s) Involved: Date of Report: Report No.: Subject: R. Shamess, Director of Engineering Services C. Curtis, Senior Project Manager, Engineering (2419) Ward 5 March 6, 2006 DTS 06-041 VOISIN GREENWAY REHABiliTATION ENVIRONMENTAL ASSESSMENT RECOMMENDATION: That the recommendations of the Voisin Greenway Rehabilitation (Stirling Avenue to the Conestoga Parkway) Municipal Class Environmental Assessment Study Report be accepted; and That Council allow the Voisin Greenway Rehabilitation (Stirling Avenue to the Conestoga Parkway) Municipal Class Environmental Assessment Study Report to submitted to the Ontario Ministry of Environment for the mandatory 30 day review period as required by the Environmental Assessment Act; and further That following the 30 day mandatory review period and Ontario Ministry of Environment acceptance of the study, implementation of the recommendations of the Study be allowed to proceed. EXECUTIVE SUMMARY: A Schedule 'B' Class Environmental Assessment Study was initiated for Voisin Greenway to develop a rehabilitation plan to address the existing and potential future concern areas along the Greenway while considering flood conveyance, natural, social and economic aspects. The limits of this study are from Stirling Avenue to the Conestoga Parkway (at Fischer Hallman Road) . The City of Kitchener retained Stantec Consulting ltd. to undertake the study and complete any design works for the preferred alternatives identified through the process. Based on various site investigations and assessments as well as from public input gained through two Public Information Centres held in December and February, various works along the Greenway are being recommended. The following table and attached figure summarize the recommendations of the report and repairs anticipated to occur in this coming summer/autumn. Area of Potential Work Failed ba wall section at 24 Ston brook Dr. Failed bagwall section at 18 Farmbrook PI. Preferred Alternative Re- rade bank and stabilize with ve etation Restore to previous condition with concrete ba s Repair gabions and immediate vicinity Minor maintenance/repairs completed as required Re air with stone Protect with stone at wall bottom Selectivel thin or remove existin ve etation Culvert inlet repair work at 136 Ruskview Rd. Area immediately upstream of Westmount Rd. Re air of various storm sewer outfalls Protection of toe erosion at various locations Ve etation mana ement within main channel In addition to these repairs, the Environmental Assessment Study Report is recommending the implementation of an annual vegetation management program as well as a visual inspection/monitoring program to identify any issues that may arise in the future. BACKGROUND: The portion of the Voisin Greenway system evaluated for the Environmental Assessment Study Report lies within Ward 5 between the confluence with Borden Greenway (at Stirling Avenue) at the downstream end and the upstream limit being the Conestoga Parkway (at Fischer Hallman Road). The Greenway is surrounded by predominantly single family residential dwellings. In its current state, the Voisin Greenway system is exhibiting numerous signs of disrepair and failure. Several locations along the watercourse are experiencing significant issues of concern including undermining, erosion, slope stability, and excessive sediment aggradation. Problems of this sort along the Greenway have been observed for a number of years with previous repairs focussed on relatively small areas of immediate concern. The City of Kitchener Stormwater Policy (2002) and subsequent Annual Audits identified a number of problem areas and coupled with recent and anticipated creek failures, prompted the current Study, which reviews the system, evaluates alternatives for repair, selects a preferred alternative, and provides a means to implement rehabilitation measures for the system as a whole. REPORT: Voisin Greenway is located in Ward 5 and drains a 510 ha component of the Schneider Creek headwater system. The reach of the Greenway system within the Study Area (approximately 2.1 km) consists largely of an engineered watercourse system that replaced and re-aligned the original natural watercourse in conjunction with the development of the area as a residential community in the 1950's. Varying bed and bank materials can be observed along the subject reach including such components as concrete bag walls, armour stone retaining structures, steel "bin" walls, bioengineering, and minor sections of earthen 'natural' channel. Throughout much of the Study Area the Greenway is confined to a narrow right-of-way between private properties, primarily of single-family residential character. In its current state, the Voisin Greenway system is exhibiting numerous signs of disrepair and failure. Several locations along the watercourse are experiencing significant issues of concern including undermining, erosion, slope stability, and excessive sediment aggradation. Problems of this sort along the Greenway have been observed for a number of years with previous repairs focussed on relatively small areas of immediate concern. In order to address the current conditions of the Greenway, the City retained Stantec Consulting Inc. to undertake a Schedule 'B' Class Environmental Assessment Study to review the system, evaluate alternatives for repair and design, and provide a means to implement rehabilitation measures for the system as a whole. In accordance with the Terms of Reference the Consultant Team completed various investigations and evaluations of existing physical conditions within the study area with an objective to secure information that would assist in the determination of an appropriate solution. Site investigations included a geotechnical/stability assessment, topographic and vegetation survey, geomorphological assessment, aquatic biology/fisheries habitat assessment and a hydraulic capacity assessment. The results of the existing conditions assessments generally conclude that the Greenway system is, by and large, functioning well from a conveyance perspective, generally stable across the majority of it's length, and of limited environmental sensitivity. The results of the Public Information Centres generally indicated that the adjacent landowners are, for the most part, very satisfied with the Greenway and long for the days of routine maintenance. The net result is that there does not seem to be a need or desire for large-scale remediative works or revisions to the existing condition, from an economic, environmental, public use, or cost perspective. These assessments, coupled with information obtained through two Public Information Centres, formed the basis for development of alternatives and selection of preferred alternatives for rehabilitation of the Greenway. Alternatives developed were evaluated based on the following criteria: cost, public acceptance, environmental impact, maintenance/long-term benefit, ease of construction, aesthetics, risk to property, conveyance, and potential for future failure. The following table summarizes the preferred alternatives and the works to be undertaken to address the problem locations along the Greenway. Area of Potential Work Failed ba wall section at 24 Ston brook Dr. Failed bagwall section at 18 Farmbrook PI. Preferred Alternative Re- rade bank and stabilize with ve etation Restore to previous condition with concrete bags Re air abions and immediate vicinit Minor maintenance/repairs completed as re uired Repair with stone Protect with stone at wall bottom Selectivel thin or remove existin ve etation Culvert inlet re air work at 136 Ruskview Rd. Area immediately upstream of Westmount Rd. Repair of various storm sewer outfalls Protection of toe erosion at various locations Ve etation mana ement within main channel In addition to these repairs, the Environmental Assessment Study Report is recommending the implementation of an annual vegetation management program as well as a visual inspection/monitoring program to identify any issues that may arise in the future. Subsequent to Council approval and Ministry of Environment acceptance of the Environmental Assessment, construction of the preferred alternatives would be scheduled for the summer/autumn of 2006. FINANCIAL IMPLICATIONS: The works described above as the preferred alternative have been included in the 2006 capital budget and it is anticipated the budget is sufficient to cover the recommended works. COMMUNICATIONS: As per the requirements of the Environmental Assessment process, several notifications have been provided to the public as well as to the required Provincial Ministries. Two notices were placed in the Kitchener Waterloo Record advertising the two Public Information Centres as well as the Notice of Intent. In addition, invitation letters to the Public Information Centres were mailed to residents backing onto the Greenway. A third letter describing the proposed works was also provided to the residents for their information and comment. It should be noted that the Grand River Conservation Authority was included on the Study Team. CONCLUSION: Recent and anticipated failures of existing bagwall along the Voisin Greenway prompted commencement of a Schedule 'B' Class Environmental Assessment to identify the need for rehabilitation of the Greenway. The results of the existing conditions assessments generally conclude that the Greenway system is, by and large, functioning well from a conveyance perspective, generally stable across the majority of it's length, and of limited environmental sensitivity. The results of the Public Information Centres generally indicated that the adjacent landowners are, for the most part, very satisfied with the Greenway and long for the days of routine maintenance. The net result is that there does not seem to be a need or desire for large-scale remediative works or revisions to the existing condition, from an economic, environmental, public use, or cost perspective. Based on these evaluations and public input, preferred alternatives to the various issues have been proposed, and budgeted for in the 2006 Capital budget. Subsequent to Council and Ministry of Environment acceptance of the recommended remedial works, construction of the proposed alternatives will commence in the summer of 2006. Carrie Curtis, P. Eng. Senior Project Manager DTS - Engineering Robert Shamess, P. Eng. Director of Engineering J