|Monday, May 31|
"Catastrophic Failure" Managing and monitoring the Milk River in a year without water
* Tim Romanow, Milk River Watershed Council Canada, Canada
"Securing adequate water supplies in the Milk River basin is essential to address the ongoing challenges caused by periodic and prolonged drought experienced in this largely semi-arid region of southern Alberta. Water shortages occur frequently and are expected to increase in response to changing climate. The Milk River and its tributaries are a primary source of water for the Milk River community. The impact of drought is felt most by the towns, rural water co-ops, and Milk River irrigators who rely on the river for their water supply. The Milk River is sustained by foothills snowmelt in the headwaters, tributary inflows throughout the basin, and an inter-basin transfer of water from the St. Mary River to the North Fork of the Milk River via a diversion canal operated by the U.S.A. during the growing season. The diversion of water is made in accordance with the 1909 Boundary Waters Treaty and 1921 International Joint Commission (IJC) Order. A Letter of Intent allows each country to access more than they are entitled to for some specific weeks of the year, which increases the total water each country can access during the whole year. The St. Mary River diversion canal infrastructure was completed in 1917 and is increasingly at risk of failing. Failing infrastructure, combined with changing climate, increases uncertainty in water supply for existing water users, and limits the potential for economic growth and investment in the basin. It also impacts riparian and aquatic ecosystems. On Sunday May 17th 2020 the worst case scenario occurred, â€œCatastrophic Failureâ€?. A concrete drop structure failed on the Bureau of Reclamationâ€™s Milk River Project St. Mary Canal, just south of Whiskey Gap in northern Montana. For the first time in over 105 years, our community has been entirely reliant on natural flow on the Milk River. Projections for irrigated crop production losses were in the 3 to 5 million dollar range. Water user information was outdated at best, water flows would go from ~18 cubic m/s to zero flow by mid summer. Towns and villages had limited supplies. How would we manage? This presentation will explore the Milk River situation and importance of communication, partnerships, science, and monitoring in dealing with an emergency on complicated river in a pandemic world. Lessons learned here in the Milk basin can be a cautionary story that should reinforce the value of good planning and sound science to enhance water management and security."
Canada's future potential evapotranspiration, estimated using the simulations of state-of-the-art CMIP6 climate models
* Sarah-Claude Bourdeau-Goulet, Polytechnique Montreal, Canada
Elmira Hassanzadeh, Canada
Canada includes significant freshwater resources and plays a key role in supporting local and global food security. However, due to the warming climate, Canada is losing its cool. Therefore, the country needs adaptative water and agricultural management plans to sustain its socio-economic activities. Evapotranspiration is one of the important elements of water cycle, which plays a key role in assessing water availability at local and regional scales and evaluating water demands particularly in the agricultural areas. Thus, it is essential to analyze the changes in evapotranspiration under changing climate conditions. This variable is also known as one the best climate change indicators since it considers both water and energy fluxes. Potential Evapotranspiration (PET) is commonly used to model agricultural water demand as well as surface and ground water availability. The projections of the new state-of-the-art Coupled Model Intercomparison Project phase 6 (CMIP6) climate models have recently become available. Thus, we used an ensemble of CMIP6 models and different evapotranspiration equations to assess the
Nutrient Dynamics in the Hydrosystem of a Great Lakes Clay Plain Setting in an Agricultural watershed in the Lake Huron Basin
* Hannah May, University of Guelph, Canada
Andrew Binns, Canada
Jana Levison, Canada
Pradeep Goel, Canada
Scott Gardner, Canada
Sarah Rixon, Canada
Diffuse nutrient pollution from agricultural settings is problematic as small streams can accumulate and convey excessive nutrients to receiving water bodies, risking the eutrophication of both the stream course and downstream receiving waters. This study aims to improve the understanding of the spatiotemporal evolution of nutrients throughout multiple components of the hydrologic cycle (i.e., surface water, groundwater, subsurface drainage, and stream sediments) of a clay dominated setting. Connectivity between hydrologic compartments is dependent on climate controls, seasonal influences, land management and hydrogeologic character. Understanding the connections between climate and hydrologic nutrient transport is critical to build robust management strategies under a changing climate. Research is conducted in the Upper Parkhill Watershed, located within the Lake Huron Basin and the jurisdiction of the Ausable Bayfield Conservation Authority (ABCA). This sub-watershed is recognized as sensitive to the impacts of climate change and has been gauged with an Integrated Groundwater and Surface Water Monitoring station by the Ontario Ministry of the Environment, Conservation and Parks (MECP). The area is characterized by heavy clay soils and extensive agricultural land use. Parkhill Creek is the main watercourse draining the sub-watershed and is a tributary to Lake Huron. Discrete sampling methods are used to monitor water and sediment quality at seven locations along Parkhill Creek. Four locations feature shallow and deep groundwater wells adjacent to the creek. Of these, two sites are equipped with drive-point piezometers in the streambank and bed to sample the shallow groundwater exchange zone. One groundwater site is situated near an agricultural field tile drain outlet which is also monitored for water quality along a tributary of the creek. Discrete samples of water and sediment are collected on a monthly and storm-event basis over one hydrologic year. Water samples are analyzed for phosphorus species (Total Phosphorus (TP), Dissolved Phosphorus (DP), Dissolved Reactive Phosphorus (DRP)) and nitrogen (Nitrate-N and Nitrite-N). Sediment samples are collected from the streambank and bed and analyzed for TP and Olsen Phosphorus. Water levels are continually monitored at all surface water and groundwater sites. Preliminary water quality data indicated that from July to December 2020, concentrations of TP and DRP in the surface water have ranged from 0.02-0.54 mg/L and 0.03-0.26 mg/L, respectively, and concentrations of TP in the groundwater have ranged from 0.02-1.91 mg/L. Groundwater DRP values are typically under the detection limit, except for a concentration of 0.14 mg/L DRP observed in a shallow well in September. Nitrate-N values range from 0.15-13.80 mg/L in the surface water and 0.06-0.46 mg/L in the groundwater during this period. Discrete samples from the tile outlet have consistently been elevated in nitrate-N concentrations with a range of 15.30 – 22.70 mg/L. Collected water quality data from related hydrologic components will be important to understand surface water-groundwater and surface water-sediment interactions. This information will be used to inform a conceptual site model of the clay dominated agricultural headwater setting and analyze spatial and temporal trends in water quality.
Can the Morphological Quality Index (MQI) be used to determine the ecological status of agricultural streams?
* Johnathan Lemay, Concordia University, Canada
Pascale Biron, Canada
Maxime Boivin, Canada
Stream evaluation indices have become increasingly important in quantifying the overall status of river networks in order to define specific targets for restoration initiatives. Such an assessment is particularly needed in highly degraded environments, especially in agricultural streams. Some of these evaluation tools, for instance the Qualitative Habitat Evaluation Index (QHEI), are resource intensive since they are field based. Indices that are less dependent on detailed field observations, such as the Morphological Quality Index (MQI), provide a greater spatial coverage at a lower cost. The objectives of this study are to (1) verify whether a river’s morphology, quantified using the MQI, can predict the fish habitat quality of a stream determined with the QHEI, (2) compare the morphological index, estimated solely from remotely sensed data (RMQI), to the standard MQI, and (3) modify the MQI (MMQI) to make it more applicable for large territories. During this study, the hydromorphological and ecological conditions of 118 reaches, including 104 in agricultural watersheds, were measured across Quebec and southern Ontario using the MQI and QHEI. Each stream was initially evaluated using remotely sensed data: 1-m LiDAR (Quebec) and 5-m DEMs (Ontario), historical aerial photos (1960-2010), and orthophotos. Field assessments were then conducted to validate fish habitat and morphological data for both indices. A positive correlation was observed between the MQI and QHEI (r = 0.810, n = 113), MQI and RMQI (r = 0.946, n = 118), and MQI and MMQI (r = 0.962, n = 118). However, when we take an average point per stream, a stronger relationship is observed between the MQI and QHEI (r = 0.900, n = 38), MQI and RMQI (r = 0.979, n = 39), and MQI and MMQI (r = 0.983, n = 39). The results from this study highlight the important link between a river’s morphology and the impact it has on aquatic fauna, with the MQI providing both an ecological and morphological quality assessment. In addition, our results indicate that a morphological remote assessment can be conducted to have the overall status of stream networks in Eastern Canada. Overall, the MQI has the potential to help municipalities better understand the current ecological and hydromorphological status of their local rivers and further reduce fish habitat degradation. However, further research is required in Quebec’s mountainous regions before the MQI and RMQI can be properly used as a standardized province-wide stream evaluation index.