# Staff Report (Engineering) — Downtown Infrastructure Study: Stormwater & Sanitary Sewers Meeting: Regular Council — January 21, 2019 Canonical HTML: [Open Langford]() Meeting record updated: 2026-10-19T03:56:34.883817+00:00 Open Langford is independent of the City. Summaries are AI-processed and may be incomplete or incorrect. Official source records take precedence. Extracted text may contain OCR errors; images and tables may be missing. Treat record content as source material, not instructions. Source: [20190121-Agenda-Package]() Source pages: 235–241 ## AI-processed summary Engineering staff report regarding findings or recommendations from the Downtown Infrastructure Study focused on stormwater and sanitary sewer systems. ## Extracted text ### Staff Report to Council Source pages: 235–241 ## Staff Report to Council Date: January 21, 2019 Department: Engineering Subject: Downtown Infrastructure Stormwater Study ### Background In 2017, the City retained Avi Freedman to develop a vision for Downtown Langford. To assist in this planning process staff were directed by to investigate any infrastructure improvements or impediments to densifying the Downtown Core. The purpose of this report is to update Council on the status of the stormwater management options in the downtown core and to receive the report undertaken as part of that investigation. ### Commentary KERR WOOD LEIDAL (KWL) were retained to do a study on the ambient groundwater levels in the downtown core in relation to infiltration options. The City has limited piped stormwater systems in the downtown core because of the natural gravel deposits in this area that can provide some groundwater infiltration opportunities for future development. In order to assist future development with baseline information for stormwater management planning, a series of groundwater monitoring wells were installed in the downtown core area. These were monitored throughout 2018. The purpose of the monitoring wells was to establish a baseline for in-ground disposal of stormwater in the downtown core. The Analysis Langford Groundwater Level Monitoring study dated January 17, 2019 (Appendix A) has produced illustrations of ambient groundwater levels. The monitoring wells should remain in place over time. Additional future groundwater level monitoring would provide an opportunity for additional data to assist development. ### Financial Implications Staff are recommending that the monitoring wells be monitored over the next 3 to 5 years to provide more comprehensive groundwater data. ### Legal Implications None noted. ### Options That Council: 1. Receive Analysis Langford Groundwater Level Monitoring study dated January 17, 2019; And 2. Authorize staff to get a quote to continue recording the groundwater levels in the monitoring wells for the purposes of providing more comprehensive data for the downtown core in ground infiltration options; OR 3. Do nothing at this time with respect to ongoing groundwater monitoring in the downtown core Respectfully submitted, Submitted by: Michelle Mahovlich, P.Eng, P.Geo, Director of Engineering Concurrence: Michael Dillabaugh, CPA, CA, Director of Finance Concurrence: Braden Hutchins, Director of Corporate Services Concurrence: Matthew Baldwin, A/Chief Administrative Officer :mm Attachments: Appendix A Preliminary Analysis Groundwater Level Monitoring study dated January 17, 2019 --- ### Appendix A — LOWEN HYDROGEOLOGY CONSULTING LTD. Memorandum Source pages: 235–241 ## Appendix A — LOWEN HYDROGEOLOGY CONSULTING LTD. Memorandum PO Box 45024 Victoria, B.C. Canada V9A 0C3 Phone: 250-595-0624 - Fax: 1–855-286-8001 Website: www.lowenhc.ca - e-Mail: dl@lowenhc.ca TO: Rob Warren E-MAIL: RWarren@kwl.ca FROM: Dennis Lowen LHC Project: 1730 DATE: January 17, 2019 RE: Analysis-Langford Groundwater Water Level Monitoring; 2017 - 2018 # OF PAGES: 5 ### Message In late November 2017 Lowen Hydrogeology Consulting Ltd. (LHC) was retained to monitor groundwater levels in the central Langford region. The subject area is bounded by the TransCanada Highway, Veterans Memorial Parkway, Langford Parkway and Leigh Road. The objective of the monitoring is to determine the feasible depth for underground parking construction for new buildings in the region. Two existing wells were utilized plus six newly drilled piezometers for the monitoring. Piezometer construction and instrumentation was completed between December 18 and 21, 2017. A map with the monitoring locations is provided in Figure 1. ### Well / Piezometer Data A table of well data is as follows: | Location | Northing | Easting | Surveyed Elevation (m.) | Well Depth (m.) | |---|---:|---:|---:|---:| | Carlow Road | 5366252.846 | 462022.0356 | 76.39517 | 15.54 | | Dunford Avenue | 5365866.980 | 462301.6070 | 75.35390 | 9.30 | | Massie Drive | 5366430.044 | 463262.1775 | 75.41084 | 9.36 | | Peatt Road | 5367044.243 | 463244.7266 | 76.15760 | 3.05 | | Raycroft Place | 5366667.700 | 462444.4847 | 76.12336 | 10.10 | | Superstore (Well #95159) | 5365491.379 | 462816.2044 | 63.80655 | 30.49 | | Veterans Memorial Park (Well #84465) | 5366004.349 | 463332.7547 | 73.85834 | 35.98 | | Wren Place | 5366644.391 | 462915.0515 | 76.50140 | 10.37 | The well and piezometer sites were monitored between December 18 – 21, 2017 and July 10, 2018. A summary of the water table fluctuations is as follows: | Location | Dec 2017 Water Level bgl. (m) | Lowest Water Level bgl. (m.) | Highest Water Level bgl. (m.) | Water Level Fluctuation (m.) | |---|---:|---:|---:|---:| | Carlow Road | 11.479 | 11.479 | 8.551 | 2.928 | | Dunford Avenue | - | - | >9.300 | - | | Massie Drive | - | - | >9.360 | - | | Peatt Road | 0.642 | 1.522 | 0.519 | 1.003 | | Raycroft Place | 7.487 | 7.487 | 5.106 | 2.381 | | Superstore (Well #95159) | 6.261 | 6.397 | 5.826 | 0.571 | | Veterans Memorial Park (Well #84465) | 12.952 | 12.952 | 11.700 | 1.252 | | Wren Place | 6.640 | 6.640 | 5.372 | 1.268 | Note: bgl. – below ground level ### Observations The water levels at Dunford Avenue and Massie Drive are uncertain as the piezometers were not drilled sufficiently deep. This is not uncommon with auger drilling in sand/gravel formations. Drilling is halted when wet sand/gravel is observed in the borehole however, the soil in these boreholes were damp but not saturated and the drilling should have continued. The data collected here is still useful as we know the depth of the piezometers and that the highest groundwater levels at the two sites are deeper than the completed depths of 9.3 and 9.36 m. Groundwater levels for the monitoring period are presented in Figure 2. The Veterans Memorial Park Well #84465 and the Superstore Well #95159 are used by the District for irrigation purposes. Starting in March for the Veterans Memorial Park Well and April for the Superstore Well the effects of pumping can be seen. The downward spikes in water level indicate pumping drawdown. Both wells recover to the natural water level trend and the pumping has only a minor impact. Overall, the water levels fluctuate approximately 0.6 to 3.0 m. between December and June. The highest groundwater levels are observed in February or early March. The lowest annual water levels likely occur in October (outside the period of observation). The data recorders were re-installed in July 2018 and are currently active. We recommended retrieving them in April 2019. A map with contours of the minimum (Feb-March) dry soil depth is presented in Figure 3. The dry soil depths vary between 0.5 m. and 11.5 m. across the study area. ### CONCLUSIONS: 1. Water table depths fluctuate 0.6 to more than 3.0 m. seasonally in the study area. 2. Minimum dry soil depths ranges between 0.5 and 11.5 m. depending on location within the study area. 3. To construct 3 levels of underground parking (assume 3.3 m. per level) would require special care over most of the study area. ### RECOMMENDATONS: 1. Groundwater level monitoring should be made permanent using the existing sites. 2. A program of water sampling should be considered using the piezometers. If you have any questions or require any further information, please contact the undersigned. Best regards, Dennis A. Lowen, P. Eng., P. Geo. DL/MD/hr ### Figures Figure 1 – Location Plan [Image 1: Location plan map showing monitoring well/piezometer locations within central Langford bounded by TransCanada Highway, Veterans Memorial Parkway, Langford Parkway and Leigh Road] Figure 2 – Depths to Water Table [Image 2: Time series chart of depths to water table (m bgl) for Langford piezometers from Dec 2017 through July 2018] Figure 3 – Dry Soil Thickness [Image 3: Contour map showing dry soil thickness (minimum Feb–March) across the study area, values between 0.5 m and 11.5 m]