Rural Lowland Drainage & Irrigation
Lowlands Irrigation Supply Update
Due to recent low precipitation in June and July, high temperature and low water level in the Fraser River, the irrigation water supply may be affected in the following areas:
- Sumas Prairie Lake Bottom - there is potential for low or no water supply toward the end of August; low tide levels are predicted for the last three weeks of August. The tide levels affect the Fraser River level, preventing staff from back flooding water into Sumas River, which is the main source for irrigation supply in Sumas Prairie; and
- Matsqui Prairie - no concerns for the irrigation water supply at this time.
Click here to view the Sumas Prairie Irrigation Zones
Click here to view the Matsqui Prairie Irrigation Zones
The City will continue to update the status of the irrigation water. For further information, contact Pardeep Agnihotri, Acting Director of Operational Services, DDI & Civic Facilities, at 604-853-5485 or firstname.lastname@example.org.
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Rural Lowland Drainage & Irrigation in Abbotsford
Prime agricultural land, created by sediment deposited by the Fraser River, is located in the areas known as Sumas Prairie and Matsqui Prairie. Both areas used to flood regularly, and are now protected from further flooding by dykes. Drainage behind the dykes is improved by pumping water over them in winter/spring months, and irrigation water is supplied in ditches in summer months.
The funds needed to maintain and operate the improvements are collected from the benefiting properties via Local Service Area levies. A Dyking, Drainage, and Irrigation Committee, one for each area, makes recommendations to Council on the disbursement of those funds, and assists staff in the administration of the improvements.
The Operations division of the Engineering Department, managed by the Manager, Drainage and Electrical, is responsible for the operation and maintenance of the drainage and irrigation pump stations, and the flood protection dykes in the Sumas and Matsqui Prairie Dyking Districts.
For irrigation zones in each Prairie, please refer to the following:
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During the summer months, snow on the mountain melts and the runoff causes the Fraser River level to rise. The Matsqui dykes are designed to prevent water in the Fraser River from entering into the Matsqui Prairie area; however, some water pooling in the prairie near the dyke may occur. This is quite common and happens around all dykes. This phenomenon is due to the pressure difference created by the high water level in the river. It is not dangerous as long as water coming out of the seepage pool* is clear. If, however, the water becomes cloudy or contains river sand, it is a sign of an active boil**. This is serious and needs to be addressed immediately.
To minimize the seepage pooling and/or a boil on you property, please avoid the following activities from May to September near the dykes.
- the removal of trees or stumps;
- deep cultivation of fields; and
- digging holes with machines.
Historical Seepage and Boil locations are shown below.
View more information on the snow survey and freshet season.
View real-time River level at the Mission gauge (08MH024).
If you have experienced seepage and/or sand boils on your property and if you are in the process of selling, please provide this information to the potential buyer.
To report water pooling on your property or to get information on the freshet season, please contact the Dyking, Drainage and Irrigation Department at 604-853-5485.
*Seepage Pool: Clear water coming out of the ground on the land side of the dyke due to pressure from high water level in the river. This is very common and is not serious.
**Piping and Boil: When the water levels in the river stay high for an extended period of time, the seepage can increase in volume and velocity. This can, sometimes, start moving sand and soil from the dyke foundation. This erosion of sand and soil is called piping. The discharge end of the active sand or soil pipe is called boil. (Source: US Army Corps of Engineering)
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Ditch Maintenance Program
The Ditch Maintenance Program is a service provided by the City to the agricultural and rural areas of Matsqui and Sumas Prairies. It includes cleaning approximately 280 km of ditches on an annual basis.
In 2012, changes were made to the Ditch Cleaning Pilot Program, in consultation with the DDI Committees and Department of Fisheries and Oceans.
The new Ditch Maintenance Program has worked well in the last few years. Minimal flooding complaints were received in both prairies. All ditch maintenance work was completed before November 30, ensuring the drainage system was ready for the rainy season. Please refer to the Ditch Maintenance Program Fact Sheet for more information on the Ditch Maintenance Program.
The ditch maintenance work is completed using a track excavator with a 3 meter wide ditching bucket. For the excavator to reach the ditches on or along your property, a clear 6 meter (20 foot) access next to the ditch is required.
Access for ditch maintenance was one of the major challenges we encountered since the new ditch cleaning program was in place. Access to some of the diches was restricted either due to crops, equipment or machinery.
To ensure the Ditch Maintenance Program is successful, it is important that clear access to the ditches on or along your property is maintained. If possible, please ensure:
- All crops and/or machinery are cleared from the land next to the ditches from September 15 to November 30 every year.
- All permanent crops such as blueberries, etc. be planted a minimum 6 meters (20 feet) away from the top of the ditch to allow clear access for cleaning.
Individual farmers will be notified to provide access at least two weeks before the excavator reaches their property.
Due to the limited cleaning window and the large number of ditches that require cleaning, if your ditch is missed due to unavailable access, staff may not be able to come back to clean your ditch. The ditch will be cleaned in the following year when access becomes available.
General information regarding ditch maintenance is provided below:
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A good Beneficial Management Practice (BMP) program will reduce soil erosion, air pollution and impacts on water quality.
In the flat areas of Abbotsford, the north east wind in the winter months blows the soil from uncovered lands and fills in the drainage watercourses. This increases the need for ditch cleaning and increases the maintenance costs. Cover crops are an excellent way to reduce soil erosion.
Please see below for guidelines to reduce wind erosion and information on the Beneficial Management Practices:
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Fraser River Bank Erosion
Five erosion arcs have formed along the south bank of the Fraser River between the northerly tip of Matsqui Prairie and Sumas Mountain since 1997. This section of river bank is prone to erosion and rock protection was placed along the bank in 1971 and 1983. Scouring along the south bank continues to be a significant problem. The river flow is changing direction causing scouring and deepening at the base of the bank. This eventually undermines the rock protection, causing the rock to move, resulting in bank erosion and movement. The erosion arcs visible above the water level are only the “tip of the iceberg” and most of the damage is occurring underneath the water level.
The latest Beharrell Road Erosion Arc appeared on Metro Vancouver Parks lands (east of Beharrell Road) after the 2013 freshet and is only 30 m away from the Matsqui Dyke. This is the highest priority site of the five arcs because of its proximity to the dyke. If left unrepaired it poses a significant threat to public safety as it could undermine the dyke protecting nearly 5,000 hectares of diverse agricultural land in the Matsqui Prairie, historic Clayburn and Matsqui Village, Matsqui First Nations and major regional infrastructure such as Highway 11, railways, National Defense Communication centre, BC Hydro towers, gas mains, water transmission main and the JAMES Wastewater Treatment Plant.
In July 2013, the City and Metro Vancouver Parks engaged the services of Northwest Hydraulics Consultants (NHC) to assess and review the Beharrell Road Erosion Arc. The assessment indicates that notable aggradation occurred in the middle of the channel starting from the Sumas Bar extending downstream to the bend near Hatzic Prairie. Notable scour has also occurred along the south bank of the river along the base of our dyke and the Matsqui Trail. Erosion protection measures were recommended to be implemented to protect the dyke from further erosion before the 2014 freshet by NHC (July 2013). The recommendation was supported by both the Ministry of Forests, Lands and Natural Resource Operations and Consultant Golder Associates (December 2013).
Design work for the Beharrell Road Erosion Arc was initiated in December 2013, with tendering and award in January 2014. Construction started in February 2014 and repair work substantially completed on March 31, 2014. Cost to repair the Beharrell Road Erosion Arc is $2.8M. The City received approval from Emergency Management BC to transfer $1.2M funding originally allocated for the Ridgedale Riverbank Protection Project under the Flood Protection Program in January 2014. The City requested additional funding from the Ministry of Justice (through Emergency Management BC) to fund the Beharrell Road Erosion Arc Repair and to protect the Ridgedale Riverbank.
New erosion arcs are expected to form along the south bank until the sources that cause the change of flow within the river are understood and dealt with. Following the completion of the repair, the City commissioned a hydraulic study to review the Fraser River bank erosion issue. Mitigation options are being proposed and finalized with input from various stakeholders. The preferred solution with cost estimates will be used to lobby senior government for funding so that the Matsqui Dyke is protected from future erosion issues.
Background information on the Beharrell Road Erosion Arc Repair Project is provided in the reports listed below:
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