USGS | GAMA

The Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) is a statewide, comprehensive assessment of groundwater quality designed to:

Describe and explain patterns in groundwater quality

Determine where and to what extent groundwater meets drinking water quality benchmarks

Determine how groundwater quality is changing at the basin scale

Identify the natural and human factors affecting groundwater quality

Click the "Select" tab to select layers.

Map Layers

Counties

Tribal Lands

Watersheds

Major Rivers

Principal Aquifers

GAMA Study Areas

STUDY AREA COLOR

	Groundwater resources used for public supply
	Groundwater resources used for domestic supply

Counties

**Data Source:** USGS

	County boundary

Tribal Lands

**Comments:** Depicts the Bureau of Indian Affairs' Indian Land Areas Map of federally recognized Tribes. Areas include Reservations, Public Domain Allotments, and Trust or Restricted Fee land.

**Data Source:** USGS

	Tribal land

Watersheds

**Comments:** Watershed boundaries are determined by hydrologic units.

**Data Source:** USGS

	Watershed boundary

Major Rivers

**Comments:** Depicts the National Hydrography Dataset (NHD) that encodes information about naturally occurring and constructed bodies of surface water (lakes, ponds, and reservoirs) and paths through which water flows (canals, ditches, streams, and rivers).

**Data Source:** USGS National Map

	Waterbody
	Stream
	Intermittent Stream

Principal Aquifers

**Comments:** Color group determines general aquifer type. Color groups are sub-divided into more detailed aquifer classifications as shown here.

**Data Source:** USGS National Water Information System: Mapper

	Blues	Unconsolidated and semiconsolidated sand and gravel aquifers
	Greens	Sandstone aquifers
	Purples	Sandstone and carbonate-rock aquifers
	Browns	Carbonate-rock aquifers
	Reds	Igneous and metamorphic-rock aquifers
	White	Other