Following is a list of terms that appear in these documents and elsewhere in the literature relevant to the Main San Gabriel Basin and its management. Many of the definitions given here are paraphrased or simplified versions of fuller definitions taken from the Judgment, Rules and Regulations, and other documents, and as such should not be construed to serve as or substitute for the precise legal definitions provided in those documents.
Aquifer
Rock or sediment in a geologic formation which is saturated and sufficiently permeable to transmit economic quantities of water.
Cyclic Storage
Storage in the Basin of supplemental water for subsequent recovery and use under a special agreement with Watermaster.
Divert
To take waters of any surface stream.
Diverter
Any party who diverts.
Fiscal Year
The period July 1 through June 30.
Groundwater
Water beneath the surface of the ground and within the zone of saturation.
Groundwater basin
An interconnected permeable geologic formation capable of storing a substantial groundwater supply.
Judgment
The Main San Gabriel Basin Judgment, a judgment of the California State Superior Court for Los Angeles County (Case No. 924128, Upper San Gabriel Valley Municipal Water District vs. City of Alhambra, et al.). The final judgment was entered in January 1973.
Key Well
A water-level monitoring well, also known as the Baldwin Park Key Well and Los Angeles County Flood Control District well #3030F. Water levels in the Key Well are continuously recorded and used, among other things, to determine when imported water may or may not be spread in the Basin.
Natural Safe Yield
The quantity of natural water supply which can be extracted annually from the Basin under conditions of the long-term average annual supply, net of the requirement to meet downstream rights.
Operating Safe Yield
The quantity of water which Watermaster determines may be pumped from the Basin in a particular fiscal year.
Overdraft
A condition wherein the total annual production from the basin exceeds the natural safe yield thereof.
Physical Solution
The court decreed method (via the Judgment) of managing the waters of the Basin so as to achieve the maximum utilization of the Basin and its water supply, consistent with the adjudicated water rights.
Produce
To pump or divert water from the Basin.
Producer
Any party who produces water from the Basin.
Relevant Watershed
That portion of the San Gabriel River watershed tributary to Whittier Narrows, and within which water rights were adjudicated by the Judgment. A map of the Relevant Watershed boundary is available, as well as a written legal description.
Replacement Water
Water purchased by Watermaster to replace water produced in excess of a producer's normal allotted share or right.
Section 28
That portion of the Watermaster Rules and Regulations which defines Watermaster's role and responsibilities in management of groundwater quality in the Basin.
Supplemental Water
Nontributary water imported into the Basin by one of the three overlying municipal water districts.
Title 22
That portion of the California Administrative Code which requires that producers of drinking water regularly monitor their wells and other sources of supply for various chemical constituents.