Why Are We Researching the South Saskatchewan River Basin?

Over the first few months of our blog, much has been written about the progress made on our satellite pasture project, and how it could help producers down the road. Today we share a brief summary of the work being done on our other project. The following abstract was put together by Aquanty to explain how a better understanding of an individual hydrologic region could help insurance providers create viable solutions for agriculture producers looking for protection against flooding and drought.

Large Basin-scale Integrated Surface-Subsurface Hydrologic Modeling to Support Agricultural Risk Management

For decision makers and stakeholders seeking to inform water management policy and to understand hydrologic risk, a watershed encompassing a few hundred square kilometers is typically the smallest area of interest; while depending on the scenarios under consideration, the region of interest can easily expand to that of a major river basin of well over one hundred thousand square kilometers in size.

Agriculture focused hydrologic risk assessments in particular tend to demand large spatial scales, on account of the large agricultural land base. Considering that overland flood damage and crop loss insurance claims due to extreme hydrologic events are expected to increase in response to climate change, it is anticipated that there is going to be a growing demand for large scale hydrologic risk assessments.

Because of the intrinsic link between comprehensive hydrologic risk assessment and hydrologic modelling, there is also a growing recognition of the benefit that complex hydrologic models can offer over their simplistic counterparts. With the advancement of high performance scientific computing resources there has been a coincident increase in hydrologic modelling capabilities.

water cycle

The hydrologic cycle.

Aquanty Inc. of Waterloo, Canada in partnership with the Alberta Federation of Agriculture (AFA), Agriculture and Agri-Food Canada, and DYMAC Risk Management Solutions Ltd., is currently developing a fully-integrated surface water and groundwater model of the South Saskatchewan River Basin (SSRB) located in western Canada. The main objective of this project is to better quantify risk to pasture and crop production (both irrigated and dryland farming) as a result of excessively dry or wet soil conditions. This includes, flood, drought, and too-wet-to-seed conditions.

The modelling approach employed for this study is to create a physics-based 3D fully-integrated surface water and groundwater model for the entire basin using Aquanty’s state-of-the-art software platform, HydroGeoSphere. This approach includes representation of overland flow using the 2D Diffusion Wave Equation, and representation of variably-saturated groundwater flow with the 3D form of Richards’ Equation. With the fully-integrated modelling approach these equations are tightly coupled and allow for a more accurate representation of surface water-groundwater interaction in comparison to loosely coupled or single domain (e.g., surface water only, or groundwater only) modelling.

The 146,000 km2 SSRB, which has its head waters in the Rocky Mountains, is a major source of water for agricultural, municipal, commercial, and industrial users in southern Alberta (AB) and Saskatchewan (SK), Canada. Much of the present-day interest in water issues within the SSRB is motivated by current and future water availability for competing uses such as agricultural water supply and in stream flow needs for aquatic species. Additional public interest in water related issues in the SSRB has been spurred by recent flooding events caused by extreme precipitation and its associated damage to urban infrastructure.

A look at the SSRB as broken down by HydroGeoSphere modelling.

A look at the SSRB as broken down by HydroGeoSphere modelling.

The construction of this model required the assembly of all relevant data for surface water and groundwater processes, resulting in a very rich database of basin information. Relevant information includes: surface information such as: topography, land use and vegetation, soils distribution, reservoir and dam operations; and subsurface information such as; geology, hydrostratigraphy, and groundwater withdrawals.

In addition to providing insight into agricultural risk, the completed model can be used to investigate the impact of hypothetical scenarios on basin hydrology. For example: what is the impact of a wetter or drier climate? Or what is the impact of land use change within the basin?

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