Arizona Hydrological Society - Technical, nonprofit society focusing on hydrologic, geologic, and environmental sciences.
Low Impact Development Center, The - Nonprofit group that develops and provides information on protecting environmental and water resources via site design techniques that replicate pre-existing hydrologic site conditions.
Minnesota Ground Water Association - A professional membership organisation that promotes the science of ground water hydrology and education on Minnesota's ground water resources.
Nebraskans First - Dedicated to preserving and protecting the groundwater for agriculture.