Simulating Hydrological Behaviour Under Environmental Change in Alberta
Sustainable environmental management requires the knowledge of the envelope of expected water availability, both in rivers and in the soil. The ACRU agro-hydrological modelling system is a model than can provide this information under a range of environmental conditions.
ACRU is a multi-purpose, multi-level, integrated physical-conceptual model that is designed to simulate total evaporation, soil water and reservoir storages, land cover and abstraction impacts, snow water dynamics and streamflow at a daily time step. As is the case with every integrated/multipurpose hydrological modelling system applied to simulate hydrological responses in large and heterogeneous watersheds, ACRU requires considerable spatial information, inter alia, on topography, a wide range of climatic parameters, soils, land cover, reservoirs, and streams. The spatial organization of sub-units in ACRU is flexible, and includes sub-watersheds, square grid cells, and hydrological response units (HRUs). For example, the 20,000 km2 upper North Saskatchewan River watershed was subdivided into 1528 HRUs, each having a unique combination of elevation, land cover, and climate. The output of the ACRU model consists of daily time series of 52 variables for each spatial modelling unit, including streamflow, groundwater flow, groundwater recharge, soil water deficit and surplus, irrigation requirements, water use by vegetation, and evaporation from wet surfaces. From the time series, risk analyses on any variable can be carried out using exceedance probability plots, which provide information on the percentage of time a certain value, e.g. flood, soil moisture, or low flow is exceeded.
Current work on the Hydro-Climatological Atlas of Alberta is also briefly presented, including the calculation of climate trends based on the instrumental record 1950 – 2010.
ACRU is a multi-purpose, multi-level, integrated physical-conceptual model that is designed to simulate total evaporation, soil water and reservoir storages, land cover and abstraction impacts, snow water dynamics and streamflow at a daily time step. As is the case with every integrated/multipurpose hydrological modelling system applied to simulate hydrological responses in large and heterogeneous watersheds, ACRU requires considerable spatial information, inter alia, on topography, a wide range of climatic parameters, soils, land cover, reservoirs, and streams. The spatial organization of sub-units in ACRU is flexible, and includes sub-watersheds, square grid cells, and hydrological response units (HRUs). For example, the 20,000 km2 upper North Saskatchewan River watershed was subdivided into 1528 HRUs, each having a unique combination of elevation, land cover, and climate. The output of the ACRU model consists of daily time series of 52 variables for each spatial modelling unit, including streamflow, groundwater flow, groundwater recharge, soil water deficit and surplus, irrigation requirements, water use by vegetation, and evaporation from wet surfaces. From the time series, risk analyses on any variable can be carried out using exceedance probability plots, which provide information on the percentage of time a certain value, e.g. flood, soil moisture, or low flow is exceeded.
Current work on the Hydro-Climatological Atlas of Alberta is also briefly presented, including the calculation of climate trends based on the instrumental record 1950 – 2010.
