Changes in Assessment Report for the Labatte-Mastronardi Drain

Transcription

1 Changes in Assessment Report for the Labatte-Mastronardi Drain Roll No , and Municipality of Leamington February 16, 2016 Project No

2 February 16, 2016 The Municipality of Leamington 111 Erie Street North Leamington, Ontario N8H 2Z9 Mayor Paterson and Members of Council Subject: Labatte-Mastronardi Drain Changes in Assessment for Parcels with Roll No , and In the Municipality of Leamington Our File Reference Authorization Pursuant to Section 65(3) of the Drainage Act, 1990, Chapter D.17, as amended 2010, the Corporation of the Municipality of Leamington appointed the firm of Crozier Baird Engineers to prepare a report for the Value of Benefit and Outlet Liability adjustments for an increase in flow volumes due to greenhouse development for the followings lands: Civil Address Roll Number Owner 400 Mersea Road Ontario Ltd. T/A West Pointe Greenhouses 410 Mersea Road New Castle Farm Ltd 414 Mersea Road New Castle Farm Ltd. This appointment considers the nature or extent of the use of a drainage works by land assessed for the drainage works is subsequently altered which is in accordance with Section 65(3) of the Drainage Act, 1990, Chapter D. 17, as amended PURPOSE OF REPORT AND CURRENT DRAINAGE REPORT New Castle Farm Ltd. and West Pointe Greenhouses have previously constructed greenhouses on lands with Roll No , and The existing development has increased the flow volumes entering the Labatte-Mastronardi Drain. The current drainage report on file for the Labatte-Mastronardi Drain is dated August 30, 1983 and was prepared by E.O. LaFontaine, P. Eng. We find that certain portions of the affected lands, located within Concession 2, north Part of Lot 4, were not previously assessed into the current report but were connected under a stormwater management report dated March 13, 2007 prepared by Bruce D. Crozier, P.Eng. In the 2007 stormwater management report it was noted that changes to the assessments would not be carried out in conjunction with the stormwater management report but could be included in the next drainage report prepared for the Labatte-Mastronardi Drain. It should be noted that parcel areas have changed since preparation of the 2007 stormwater management report. Using the Municipality of Leamington s online mapping system, updated parcel

3 areas have been obtained for each of the three parcels. These updated areas have been used to calculate the assessment adjustments described in Section 6 of this report. 3.0 EXISTING DRAINAGE CONDITIONS We have established the land area affected by this report and have prepared a plan, found in Appendix A, illustrating the boundaries of the affected lands and the existing greenhouse development. Under the 2007 stormwater management report, a 375 mm diameter smooth-walled pipe was installed from the existing catch basin at the centre of the existing pond on lands with Roll No to a proposed pumping station as outlined in the 2007 stormwater management report. A 200mm diameter smooth-walled pipe conveys water from the pumping station to a concrete manhole near the south limit of the Mersea Road 3. A 300 mm diameter smooth-walled pipe connects the concrete manhole to the Labatte-Mastronardi Drain. Further, a 200mm diameter pipe provides a gravity outlet for drainage of West Pointe Greenhouses and is shown and considered in the 2007 stormwater management report. 4.0 ALLOWABLE RELEASE RATES AND STORMWATER MANAGEMENT The March 13, 2007 storm water management plan shows that storm water management practices are being utilized for the existing greenhouse development. This plan further illustrates that no additional flow restrictions are required as the existing pipe and a proposed pump network shall provide sufficient outlet restriction. Calculations have been undertaken to determine the capacity of the Labatte-Mastronardi Drain and whether this capacity is sufficient to accept the increased flow from the existing greenhouse developments. The calculated capacity of the Labatte-Mastronardi Drain at the designated outlet is L/s. According to the 2007 stormwater management report, the maximum allowable release rate for the post development lands is L/s. However, the owners requested that the allowable release rate be reduced to L/s, being approximately one third of the allowable release rate. As per the 1983 LaFontaine report, the flow generated by the upstream affected lands at the designated outlet point is L/s. By summing the stormwater release rate and the current flow through the drain, we have determined that the total flow through the Labatte-Mastronardi Drain at the designated outlet point would be L/s; the remaining drain capacity equals L/s. Therefore, we have determined that the Labatte-Mastronardi Drain has sufficient capacity to accept the increased flow volume from the combined hectare greenhouse development on the three parcels. Providing that the proposed stormwater management plan has been executed as described in the 2007 stormwater management report, including disconnection of the existing outlet from the E.J. Stockwell Drain, we do not anticipate capacity issues with the Labatte-Mastronardi Drain. 5.0 ASSESSMENT FOR INCREASED FLOW VOLUMES The increased Value of Benefit and Outlet charge shall be based on the increased flow volumes from the already assessed portions and those portions now utilizing the Labatte-Mastronardi Drain as outlet as per the 2007 stormwater management report. 2

4 3 6.0 ASSESSEMENT ADJUSTMENTS FOR INCREASED TOTAL FLOW VOLUME Labatte-Mastronardi Drain We would recommend that the affected parcels have the Value of Benefit, Value of Outlet and Total Value amounts adjusted to reflect the increased total flow volume resulting from greenhouse development. It should be noted that the Value of Injury Liability column in the 1983 report for the Labatte-Mastronardi Drain has not been updated as part of these calculations. Based on the greenhouses and other impermeable areas located on the subject parcels, we would recommend that the following changes be made to the Schedule of Assessment as shown in Table 1, below. Table 1. Labatte-Mastronardi Drain Assessment Adjustments Roll No Current Owner *West Pointe Greenhouses New Castle Farm Ltd. New Castle Farm Ltd. Current Assessments Value of Benefit Affected Area (ha) Value of Outlet Total Assessment Affected Area (ha) Updated Assessments Value Value Total of of Assessment Benefit Outlet , ,666 11,381 19, ,669 1,907 3, ,338 7,121 12, ,955 19,812 33,767 Updated Total on Lands 26,959 38,314 66, Updated Total Assessment 83,914 *Note: Complete name of parcel owner is Ontario Ltd. T/A West Pointe Greenhouses In accordance with Section 65 (3) of the Drainage Act, 1990, Chapter D.17, as amended 2010, we would recommend that the values in the August 30, 1983 Schedule of Assessment, being part of the current drainage report, be amended as shown for the affected parcels. We would further recommend that any future maintenance work be assessed on a pro-rata basis in accordance with the attached Maintenance Schedule of Assessment. E.J. Stockwell Drain We would recommend that the lands with Roll No , and be removed from the E. J. Stockwell Drain provided that the Municipality receives confirmation that the stormwater management pond has been disconnected from the drain as described in the stormwater management report. A new report is currently being prepared for the E.J. Stockwell Drain and we would recommend that any changes to the assessments related to the subject parcels be undertaken through this report. 7.0 SUMMARY AND RECOMMENDATIONS We have determined that the increased flow volumes for lands with Roll No , and will not adversely affect the Labatte-Mastronardi Drain if the release rate is limited to the modified 1:2 year pre-development runoff as stated in the 2007 stormwater management report.

5 The stormwater management report included the requirement that the existing 900mm diameter CSP catchbasin be modified so that the pond s outlet would be disconnected from the E.J. Stockwell Drain thereby removing the lands from that drainage area. We would recommend that the Municipality of Leamington confirm that the catchbasin has been modified and that the lands have been disconnected from the E.J. Stockwell Drain concurrently with preparation of the new report for that drain. The post-development assessment coefficient utilized for assessment adjustments to greenhouse developments is 1.5 times that of agricultural lands. We have determined the updated Values of Benefit and Outlet to be paid by lands with Roll No , and These amended values represent the increase in flow volume from the developed site. Based on the above information, we would recommend that the Municipality of Leamington assess 100.0% of the costs associated with this report equally to lands with Roll No , and All of which is respectfully submitted. CROZIER BAIRD ENGINEERS, PLANNERS AND ARCHITECTS 27 PRINCESS STREET, SUITE 102 LEAMINGTON, ONTARIO N8H 2X8 Halliday P. Pearson, P. Eng.

6 5 APPENDIX A DRAINAGE AREA PLAN FOR LABATTE-MASTRONARDI DRAIN AND PARCELS WITH ROLL NO , AND

7 DRAINAGE AREA PLAN SCALE: N.T.S 27 PRINCESS STREET, UNIT #102 LEAMINGTON, ONTARIO N8H 2X8 A DIVISION OF MATTHEW J. BAIRD CONSULTING SERVICES INC. PROJECT TITLE: LABATTE-MASTRONARDI DRAIN CHANGES IN ASSESSMENT FOR PARCELS WITH ROLL NO , AND IN THE MUNICIPALITY OF LEAMINGTON SHEET TITLE DRAINAGE AREA PLAN HALLIDAY P. PEARSON, P.ENG. DRAWN BY: SCALE: D.B. N.T.S. CHCK'D BY: SHEET No. : H.P. 1 OF 1 DATE: FEB. 16, 2016 PROJECT No. :