Glaciers delay melting and runoff from seasonal snow until late in the summer. Within a glacierized catchment, they also supplement rainfall and seasonal snowmelt with meltwater from glacial ice. Within a given glacier, there can be year‐to‐year variations in meltwater storage and runoff. However, a few generalizations are possible.
Glacier runoff has a pronounced diurnal cycle on small alpine glaciers, due to the radiation-driven diurnal melt cycle. There is typically a delay of several hours between peak melting and peak runoff, as measured by discharge at the glacier terminus.
On larger glacier systems, delays can be much greater and the discharge is more diffuse, due to the distribution of path lengths and hydraulic efficiencies in different parts of the glacier drainage system.
The glacier drainage system evolves on seasonal timescales. Early in the melt season, the drainage system does not yet have the capacity to drain the influx of surface meltwater and there is temporary storage of meltwater on the surface, englacially, and at the bed.
As the melt season progresses, saturation of the snow and firn aquifers and elimination of the supraglacial snow cover cause increased inputs to the englacial and subglacial systems, which develop increased connectivity and a greater drainage capacity.
Glacier discharge exceeds meltwater inputs as stored water is evacuated. Late in the melt season, stored water has been flushed and the mature drainage system is highly efficient, leading to rapid throughput and daily discharge totals similar to the daily meltwater inputs.
Through the winter, meltwater shuts down on glaciers in the Rockies. Void of water, subglacial and englacial conduits creep closed and the channelized drainage system in most valley and outlet glaciers shuts down. Free water is still present at the base of the glacier throughout the winter and is sometimes evident through trickling subglacial outlet streams or artesian upwellings in the glacier forefield, signalling drainage through the shallow groundwater system. Most glacial streams freeze up in the winter, with negligible discharge, although some streams remain active underneath a mantle of river ice and snow.
Glacier contributions to runoff can be a significant fraction of total annual discharge in catchments with a large glacierized area. Glacier inputs dwindle as one goes progressively downstream in most alpine settings, as a result of glaciers making up a smaller percentage of the landscape.
In the eastern slopes of the Canadian Rockies, glacier inputs to the Bow River at Banff can exceed 50% in late summer of a dry year, although glacier melt constitutes only 2% of the average annual. Annual discharge statistics therefore mask the importance of glacier contributions to stream flow. In most summers in the Canadian Rockies, seasonal snow persists until July at low elevations on the glaciers, and until August at higher elevations. There is little seasonal snow remaining elsewhere in the mountains at this time. Once this snow cover is removed, glacier runoff is dominated by melt from the low-albedo glacier ice. In summers of drought, groundwater recharge and ice melt are the sole sources of sustenance for the mountain streams.
Glacier runoff is proportional to available melt energy, whereas runoff in non-glacierized catchments is governed by precipitation. This means that discharge from glacierized catchments is less sensitive to weather fluctuations, with a supply of runoff in periods of drought that is lacking in other non-glacierized catchments. Total annual runoff in glacierized catchments varies interannually as a function of glacier mass balance, depending if:
In the latter case, specific runoff (discharge per unit area of the landscape) from glaciers exceeds that from the rest of the catchment. That is, glaciers offer a supplement to the runoff associated with rainfall and seasonal snowmelt. This may also be true in the first case, despite a positive annual glacier mass balance, as glaciers often act as snow-traps and generate greater annual snowmelt than non-glacierized areas in a catchment.
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Ross has extensive executive experience in Operations, Governance, Information Technology and Strategy at the board and senior management level including Mancal Corporation, Mancal Energy, Highridge Exploration and Atlantis Resources. He has worked in Oil and Gas, Coal, Commercial Real Estate, Portfolio Management, Recreation, Retail and Water and Wastewater Treatment. His experience is also geographically diverse having overseen operations in Canada, the United States, United Kingdom and Northern Ireland. Additionally, he has been on the board of companies with operations in Argentina, Azerbaijan, Barbados, Kazakhstan, and Russia. He has served on numerous Public, Private and Not for Profit Boards across a number of industries.
Ross has been active on several industry Boards and committees including the Canadian Association of Petroleum Producers (CAPP) and The Schulich School of Engineering Industry Advisory Council at the Schulich School of Engineering.
Brian is a seasoned Cleantech entrepreneur with a proven history of successfully bringing complex water technologies to the market. With over 25 years of experience, he has led various organizations to achieve significant milestones in the industry.
Having started as the founding CEO of the Pressure Pipe Inspection Company (PPIC) and later taking the helm at the Water Technology Acceleration Project (WaterTAP), Brian’s entrepreneurial spirit has been instrumental in driving innovation and growth within the sector.
He is an active investor in the cleantech sector and has served on many boards including the Ontario Clean Water Agency.
Actively engaged in industry associations like AWWA, WEF, IWA, and ASCE, Brian enjoys collaborating with fellow professionals to promote advancements in the field.
Brian holds an undergraduate degree and a PhD in Physics from Queen’s University, which has provided him with a solid technical foundation. As a member of the Institute of Corporate Directors, he brings valuable insights to corporate governance.