Investigating Erosion and Water Supply
Water Supply as it Relates to Erosion and Deposition in the Milk River Watershed

A new project that the Milk River Watershed Council Canada will be undertaking in 2007.

Background:

Understanding how water management impacts both water supply and streambank stability is a priority for the Milk River Watershed Council Canada.  This project has multiple objectives that will help us understand the erosion process and potential future impacts of increased water diversions from the St. Mary River.

Some of the impacts of streambank erosion in the Milk River are:
  • siltation in dugouts and reservoirs,
  • wells, pump sites and irrigation infrastructure located in the floodplain may be at risk due to erosion,
  • irrigation equipment has a limited lifespan due to abrasive sediments wearing out seals and brass piping,
  • sediments clog intakes and pipe resulting in a higher degree of "down" time for Milk River water users.
Landowners living along the Milk River are also concerned about the impact of erosion on their river banks and real estate!

Project Objectives:

Phase I
  1. To document the occurrence of erosion and identify the processes contributing to erosion in the Milk River watershed (e.g. groundwater seepage), diverted flows from the St. Mary River, land use).
  2. To understand and model the rate and extent of erosion that the expected increase in flow from the St. Mary River may have on Milk River morphology. Rationale: Increased erosion may result in a wider channel and a shallower Milk River during periods of low flow. This could jeopardize water supply infrastructure (e.g. wells, pump sites), water quantity if evaporative losses and sediment loads increase, and aquatic health due to increased water temperatures and alteration of riparian habitat.
  3. To estimate the amount of sediment that will be transported through the system and its impact on water quantity and water quality in the Milk River.
  4. To understand how the aquatic system (e.g., riparian health, fisheries) may respond to the expected changes in river morphology.
  5. To explore management options (e.g., timing of spring diversion from St. Mary River, water storage alternatives) that could alleviate some of the damage caused by erosion.
  6. To report on the occurrence and extent of erosion, on the river's capacity to carry water and on sediment loads in the Milk River 2007 State of the Watershed Report.
Phase II
  1. To set up a long-term erosion, river migration, water depth, discharge and water quality monitoring program that will document changes to river morphology through time.
  2. To identify hot spots for implementation of erosion control structures, including bioengineered techniques.
  3. Identify best management practices and stewardship activities that will lead to more stable river banks (e.g., bioengineering, management) to reduce risks and impacts on water quantity and quality.
Phase III
  1. To disseminate information regarding erosion through a factsheet publication and workshop presentations to address landowner concerns regarding a quality water supply in the Milk River Watershed.
Project Partners:
  • Milk River Watershed Council Canada
  • Agriculture and Agri-Food Canada - PFRA
  • Cardston County
  • County of Warner
  • County of Forty Mile
  • Alberta Environment
  • Sustainable Resource Development
We would like to thank the Prairie Farm Rehabilitation Administration of Agriculture and Agri-Food Canada for their generous support!
Milk River Watershed Council Canada