Increasing water supply availability and reducing treatment costs were the key issues probed at an educational conference sponsored by the American Ground Water Trust and the American Institute of Hydrology. The program, titled, "Alluvial Aquifers: Options for Development," took place May 11 in suburban-Chicago, and focused on technologies other than vertical wells used in water resources development from alluvial aquifers.

Included were presentations on wells, collector wells, infiltration galleries and horizontal directional drilling. The first half of the conference covered issues related to supply economics for users, including considerations of yield and quality. The format then turned to real-life case studies of technology applications and site-specific design criteria. (Look for an article based on the conference's water treatment seminar in the next issue of National Driller.)

Much of America's urban and industrial development has taken place in river valleys, in the same places where alluvial aquifers occur adjacent to rivers. While vertical wells frequently have been the tool to tap into these alluvial aquifers, other techniques are available to develop this resource. These techniques include collector wells, infiltration galleries and horizontal wells. America's population is expected to reach 380 million by 2050. Water needs for drinking supplies, industrial use, cooling and irrigation continue to increase. Many rivers are stressed. Many traditional aquifers already are developed. There still is considerable scope for the imaginative use of alluvial aquifers for additional water resources development.

Using groundwater under the influence of surface water is a recognized technique for accessing water from the hydrologic system. Water from lakes, reservoirs and rivers can be abstracted by inducing recharge to alluvial aquifers beneath or adjacent to surface water. Non-turbid water drawn from a geologic environment is less expensive to treat than surface water. Selecting the technology for alluvial aquifer development is an important aspect of the growing water management strategy of conjunctive use. Using alluvial aquifers rather than dams and diversions also has the potential to reduce the economic costs and the environmental consequences associated with direct river engineering.