Dates: October 2006—September 2009
Physical, Biological and Chemical Implications of Mid-Winter Pumping of Tundra Ponds: Operational Watershed Modeling Tools to Support North Slope Field Operations and Water Use
The oil industry and support services withdraw water from freshwater lakes and ponds to build ice roads and pads in the Arctic for increased access to remote sites. This technique is important to the oil industry in that it allows oil field development or maintenance while avoiding the environmental disturbance associated with construction of gravel roads and pads. Construction of ice-roads and pads begins in December or January, when the tundra mat is adequately frozen to support construction traffic, and continues through April (depending upon weather). The number of miles of ice roads constructed per year has fluctuated over the last 20 years; however, ice road construction has recently increased (see Figure 1). While the need for ice roads increases, the season during which ice road construction is permitted is decreasing (see Figure 2). The decrease in the time during which ice roads can be used is due to a changing climate. Ice roads are constructed using water from ponds, lakes, and rivers. Rivers themselves are traversed using ice bridges. The industry must have all drilling equipment back to gravel bases before the ice road deteriorates. The season ends when the first ice bridge is washed out. The ice bridge failures are a function of melting further south in the stream’s headwaters.
In spite of industry dependence on ice roads, numerous questions persist regarding when the ice road building season will begin and end, as well as potential environmental consequences of water withdrawal. All aspects of ice road construction and use are a function of both local and regional scale climate, on a daily and seasonal basis. Recent evidence suggests that the season during which ice roads are possible is decreasing as the arctic summer season lengthens. A shortening of the ice road season has a significant financial impact on the oil and mining industries and the state. Possible effects of pumping tundra ponds in winter also include impacts on the water balance, direct impacts to aquatic organisms (including fish and invertebrates), and impacts to pond water chemistry (with subsequent effects on aquatic creatures). There may also be associated cumulative impacts, as ponds are repeatedly pumped year after year. Questions have also been raised on pumping ponds and the consequent effects on neighboring (and potentially connected) unfrozen zones within rivers that serve as over-winter fish habitat.
State and Federal agencies are in need of land management tools that incorporate short and long term climate forecasts and trends. This project leverages an existing project, funded by the Department of Energy, to study the impacts of tundra pond pumping on pond chemistry. We develop management tools for state and federal agencies that regulate tundra pond pumping and ice road construction, incorporating the effects of changing seasonality. In the future, we will broaden this area to include the seasonality of ice roads and the impacts of a shortened season on resource exploration and development.
Phase I of this investigation revealed that chemical and physical impacts of mid-winter pumping were undetectable at the current accepted levels of water removal; however, at present there are no standards to guide industry and agencies in selecting reasonable limits on water removal. Considering the potential for changing baseline conditions, cumulative impact evaluations will need to rely on the understanding of process, as well as on data collection over the period of field activities. Guidelines and analysis tools are needed to enable planning for exploration and construction efforts and to ensure adequate environmental protection.
Our previous research has resulted in immediate and valuable benefits to industry and to state and federal agencies by providing a quantitative measurement of the effects of the current levels of water use from tundra lakes. Phase II of the research generates modeling tools to help improve the process of estimating available water for various uses and provide a proactive approach for evaluating water use permits and needs. By the close involvement of industry, agency, and environmental partners, we anticipate the outcome will also yield a more uniform and predictable permitting environment. The modeling tools help determine reasonable water use limits based on watershed areas, specific lake capacity, and recharge potential. They also include model tool components for estimating geochemical impacts of natural lakes’ freezing and water use. Although site specific hydrologic parameters will need to be determined, it is anticipated that this approach will be broadly applicable across Alaska and future development efforts. It will also be applicable to the many rural communities depending on lakes for their water supplies. The added value of RISA is the integration of the Weather Service and the River Forecasting Service to predicting long and short term trends in seasonality into the management tools.
This research is a combination of a hydrological, chemical, and meteorological field study, remote sensing analysis, and numerical modeling study. We quantify the water inputs and evaporative losses across the operational region of the North Slope of Alaska. Extensive snow surveys prior to spring melt allow us to characterize regional differences in snow distribution. Evaporation and evapotranspiration are empirically determined from meteorological measurements. We characterize the available recharge for a range of watersheds representing various lake-watershed characteristics. These results are combined to estimate the water balance of target lakes. The modeling and analysis efforts generate a set of operational modeling tools for industry and agencies to use for water-use activities.
Participation involves the scientific community, regulatory agencies, the oil industry, and environmental groups. British Petroleum Exploration (BPX), Conoco-Phillips Alaska Inc. (CPA), the Nature Conservancy (NC), and the Northern Alaska Environmental Center (NAEC) have joined this investigation as committed and active partners. Scientists from the State of Alaska Department of Natural Resources, and Bureau of Land Management have agreed to work closely with UAF. All team members participate during investigation planning meetings to design the research workplan, during analysis meetings to discuss interim findings (in the event that a mid-course diversion is necessary), and during the evaluation of the final report. All team members and appropriate agency representatives also participate occasionally in field sampling. BPX and CPA environmental offices assist by sharing their previously collected data and coordinating pumping by on-site contractors. They have also generously offered periodic access to facilities for time-sensitive analyses.