LIVING WATER SMART IN BRITISH COLUMBIA: “More hard surfaces in the uplands means more surface runoff volume is discharging into the agricultural lowlands. And the increased flows in streams are over longer durations. This is the real issue,” stated Ted van der Gulik, former Senior Engineer in the Ministry of Agriculture, when he explained the ARDSA criteria that have defined design practice for a half-century
Note to Reader:
The ARDA program (Agriculture Rural Development Agreement) of the 1960’s and early 1970’s was a Federal and Provincial capital projects program that funded rural agriculture development. This program was followed by ARDSA (Agriculture Rural Development Subsidiary Agreement) in the late 1970’s and early 1980’s.
Both programs encompassed rural irrigation water supply, rural drainage infrastructure as well as rural electrification. Funding was provided on a maximum formula of 75% from the program and 25% from the local partner.
Originally published in May 2017, the following article is about the “ARDSA criteria” that have defined standard engineering practice for a half-century. Understanding ARDSA criteria remains relevant to the policy, program and regulatory framework for land and water stewardship in this province, especially in the wake of the devastating Fraser Valley flooding that occurred in November 2021.
Genesis of Agricultural Drainage Criteria
Originally titled What the “Whole-System, Water Balance Approach” means for Lowland Drainage in British Columbia, the article published by the Partnership for Water Sustainability connected the dots between past, present, and future. Ted van der Gulik, former the Senior Engineer in the BC Ministry of Agriculture, explained the genesis for agricultural drainage regulatory objectives in British Columbia.
“The ARDSA criteria were used to determine the capacity of drainage ditches and pump stations for all ARDA and ARDSA projects that were approved for funding. The ARDSA criteria for operation of a regional lowland drainage system boil down to three numbers: 2, 5 and 10,” stated Ted van der Gulik.
“Once the rain stops, the system must be able to remove runoff after 2 days during the growing period (March through October); and after 5 days during the dormant season (November through February).”
“The number 10 refers to the 5-day, 10-year storm. Between storms the depth to the water level in drainage ditches needs to be 1.2 m (4 feet) to allow subsurface drain tile systems to operate properly and promote proper root and plant growth.”
“It has been many years since these drainage criteria were developed by the Ministries of Agriculture and Environment in support of the ARDA and ARDSA programs. A key message is that the 2-5-10 criteria have stood the test of time.”
“Although reference continues to be made in engineering reports to the ARDSA drainage criteria, there is an absence of recognition of the underlying cost-benefit rationale for the 2-5-10 criteria. I believe this reflects a loss of understanding that could have potentially serious implications for current and future decision-making”
“Clearly, there is a need to inform and educate a new generation of practitioners and decision-makers about the thinking and the analytical process that resulted in the ARDSA drainage criteria. This would help equip a new generation to make knowledge-based decisions.”
TO LEARN MORE:
To read the complete story, download a PDF copy of Living Water Smart in British Columbia: Restore Hydrology in the Uplands to Protect Agriculture in the Lowlands.
