North Slope Decision Support System: Multi-Objective Planning for Ice Road Routes
Authors: Brumbelow Kelly , McDonald Walter , Bourne Stephen F. , Schnabel William F. , Tidwell Amy 
Published: December 2011

On the North Slope of Alaska, ice roads and ice pads provide a cost-effective means of oil and gas exploration with minimal impact to the sensitive underlying tundra. They have become integral to oil and gas exploration activities. Their widespread use represents a challenge to water resource managers, however, due to the large volume of water required to construct and maintain them - water that is typically extracted from the many lakes that dot the landscape. Crucial questions on water balance and ecosystem impact must be considered in the state regulatory process that permits construction of these ice structures. More importantly, these questions must be considered by the community of North Slope stakeholders together in order to arrive at equitable plans that satisfy stakeholder objectives of economic development and environmental and cultural preservation.

Under a grant from the National Energies Technology Laboratory of the U.S. Department of Energy, the North Slope Decision Support System (NSDSS) is currently being developed as a system the stakeholder community can use together in the ice road planning process. Major modules of the DSS include information systems, natural system models, and planning and management functions. Development of the DSS is a collaborative effort of academic and industry personnel with significant stakeholder involvement from multiple agencies of local, state, and federal government, private energy companies, and non-governmental organizations.

NSDSS includes multi-objective planning routines for ice road routes. Pareto-optimal route alternatives are determined for cost, travel time, completion date, and other objectives. Spatial search domains are built using geographic information system (GIS) layers for a range of variables including water availability, vegetation and wildlife sensitivity, and topography, among others. Ant Colony System (ACS) optimization is utilized with novel algorithms for graph pre- and postprocessing to improve solution efficiency. Output from the planning routines allows decision makers to understand tradeoff relationships among objectives. The ice road planning (IRP) algorithm includes water balance analysis to understand likely long-term impacts on regional water resources and possible adaptation measures.

Introduction

The North Slope of Alaska is a region rich in a variety of natural resources. About one-quarter of U.S. petroleum production occurs in the region, and the full extent of oil and gas resources located on- and off-shore is still being discovered. The harsh environment hosts unique human civilizations, flora, and fauna, and industrial development impacts on all of these are of continual concern. To minimize environmental impact, on-shore exploration for energy resources occurs in the winter; the tundra landscape is frozen and less susceptible to long-term disturbance. O further protect the land surface, ice roads and ice pads are constructed on the ground and used for transport and staging. These ice roads and pads are built from liquid water pumped from the many lakes in the region and from packed snow cover.