• Trend Network for Ground Water
• Rice Land-Use Survey
• Urban Land-Use Survey
• Major Aquifer Study
• SWQA

The primary goal of the Trend Network is to systematically assess long-term trends in the chemical and physical quality of the Nation's ground water and to relate observed trends and changes to probable causes.

The Sacramento Basin NAWQA will resample wells from the Cycle I Major Aquifer Study (formerly known as study-unit or sub-unit survey), from the agricultural land-use study in rice areas, and from the urban study in the metropolitan area of Sacramento on a decadal schedule. A subset will be sampled biennially to determine the adequacy of the decadal and biennial sampling. The urban land use study well network is nested within the major aquifer study well network and the rice land-use study is partially nested.

A total of 23 shallow monitoring wells in rice areas were sampled in Cycle II for a wide range of constituents at low levels. Twenty-one wells were resampled from Cycle I. Two new wells were drilled to supplement the well network.

A total of 25 shallow monitoring wells in recently urbanized area in the metropolitan area of Sacramento were sampled in Cycle II for a wide range of constituents at low levels. Eighteen wells were resampled from Cycle I. A total of seven wells were added to the Cycle I Urban Land-use Study network following the guidlines set for well selection in Cycle I. Five wells were drilled in FY06 and two existing monitoring wells were incorporated to supplement the well network.

Reference:
Hitt, K.J., 1994, Refining 1970's land-use data with 1990 population data to indicate new residential development: U.S. Geological Survey Water-Resources Investigations Report 1994-4250, 15p.

Squillace, P.J. and Price, C.V., 1996, Urban Land-Use Study Plan for the National Water-quality Assessment Program: U.S. Geological Survey Open-File Report 1996-217, 19p.

The Major Aquifer Study well network is scheduled to be resampled in FY08.

Source Water Quality Assessment (SWQA) is a new activity for Cycle II. Source water (raw, untreated ground water) from 15 community water supply wells and finished water (treated ground water) at the same sites in the Sacramento urban area will be sampled in FY07 and analyzed for a comprehensive list of constituents.