Western Canal 2016 BMO 1 BASIN MANAGEMENT OBJECTIVES WESTERN CANAL WATER DISTRICT SUBINVENTORY UNIT Butte County Water Advisory Committee Member – Anjanette Shadley Contact Information: Phone Number: 530-342-5083 Email Address: [email protected]Description of the Western Canal Sub-Inventory Unit – The Western Canal Sub-Inventory Unit (SIU) covers an area of about 44,750 acres. About one-third of the sub-inventory unit is in the West Butte Inventory Unit and the remainder is in the East Butte Inventory Unit. The Western Canal SIU corresponds roughly to the Butte County portion of the Western Canal Water District. A portion of the southwestern corner of the water district is in Glenn County. Agricultural production in the Western Canal SIU consists primarily of rice supported by surface water in normal water supply years. The data presented in this section includes the entire Butte County portion of the Western Canal SIU. Management Objective – To maintain sufficient volumes of groundwater in storage within the Upper and Lower Tuscan Formation aquifer systems to provide an adequate and affordable irrigation water supply, of adequate quality for agriculture purposes, including during periods of extended drought and to assure that groundwater in storage is not depleted over time. It is the intent of this management objective to assure a sustainable agricultural water supply now and into the future and to assure the water supply can be utilized without injuring groundwater quality or inducing land subsidence. The management objective is also to assure an adequate supply for groundwater from the alluvial aquifer system for all domestic users in the sub-inventory unit. Geologic Formations Identified In Sub-Inventory Unit - Geologic formations in the Western Canal SIU from youngest (shallowest) to oldest (deepest) include: Basin Deposits Laguna Formation Tuscan Unit C (Upper Tuscan) Tuscan Unit B (Lower Tuscan) Fresh Water-bearing Units - In the Sacramento Valley Region of Butte County, fresh groundwater-bearing units include, from youngest (shallowest) to oldest (deepest), the Modesto, Riverbank, Laguna, Tehama and Tuscan Formations. Those included in the Western Canal SIU are: Laguna Formation Tuscan Unit C (Upper Tuscan) Tuscan Unit B (Lower Tuscan)
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Western Canal 2016 BMO 1
BASIN MANAGEMENT OBJECTIVES WESTERN CANAL WATER DISTRICT SUBINVENTORY UNIT
Butte County Water Advisory Committee Member – Anjanette Shadley Contact Information: Phone Number: 530-342-5083 Email Address: [email protected] Description of the Western Canal Sub-Inventory Unit – The Western Canal Sub-Inventory Unit (SIU) covers an area of about 44,750 acres. About one-third of the sub-inventory unit is in the West Butte Inventory Unit and the remainder is in the East Butte Inventory Unit. The Western Canal SIU corresponds roughly to the Butte County portion of the Western Canal Water District. A portion of the southwestern corner of the water district is in Glenn County. Agricultural production in the Western Canal SIU consists primarily of rice supported by surface water in normal water supply years. The data presented in this section includes the entire Butte County portion of the Western Canal SIU. Management Objective – To maintain sufficient volumes of groundwater in storage within the Upper and Lower Tuscan Formation aquifer systems to provide an adequate and affordable irrigation water supply, of adequate quality for agriculture purposes, including during periods of extended drought and to assure that groundwater in storage is not depleted over time. It is the intent of this management objective to assure a sustainable agricultural water supply now and into the future and to assure the water supply can be utilized without injuring groundwater quality or inducing land subsidence. The management objective is also to assure an adequate supply for groundwater from the alluvial aquifer system for all domestic users in the sub-inventory unit. Geologic Formations Identified In Sub-Inventory Unit - Geologic formations in the Western Canal SIU from youngest (shallowest) to oldest (deepest) include: Basin Deposits Laguna Formation
Tuscan Unit C (Upper Tuscan) Tuscan Unit B (Lower Tuscan)
Fresh Water-bearing Units - In the Sacramento Valley Region of Butte County, fresh groundwater-bearing units include, from youngest (shallowest) to oldest (deepest), the Modesto, Riverbank, Laguna, Tehama and Tuscan Formations. Those included in the Western Canal SIU are: Laguna Formation
Tuscan Unit C (Upper Tuscan) Tuscan Unit B (Lower Tuscan)
Western Canal 2016 BMO 2
BMO Key Wells Selected for Groundwater Level Monitoring (Specific Depth Method) – SPRING The Western Canal SIU uses the specific depth method to establish alert stages. As described in Butte County Code, Chapter 33A, this method sets alert stages for spring levels only.
Other wells monitored in the SIU have short periods of record and therefore do not have assigned alert levels. However they are tracked to monitor changing groundwater conditions from year to year. These include: 19N02E07K002-004 a multi-completion well added in 2006 19N02E13Q002-003 a multi-completion well added in 2006
19N02E13Q001 a monitoring well added in 2002 20N02E15H001 and 20N02E15H002 monitoring wells added in 1995 BMO Key Wells Selected for Groundwater Quality Monitoring– Groundwater Temperature (oC)
BMO Key Well(s) Selected for Land Subsidence Monitoring– State Well Number 20N01E18L003M, located within the SIU is monitored continually. Maximum annual inelastic land subsidence shall not exceed 0.01 feet per year. Western Canal Water District SIU Stakeholder Issues and Recommendations Current Conditions – Approximately 1000 acres transitioned in 2013 from rice to walnuts in the northeast corner of the District boundary at Nelson/Shippee Road at Gage Road using a mix of ground and surface water where it was traditionally served by surface water only. Additional conversion of historic row and rice commodities to orchard crops has been observed on the north-west District border at Grainland. In cooperation with the Department of Water Resources and Richvale Irrigation District, the District added five additional static water level locations to its existing monthly monitoring grid to assist in assessing drought conditions on a short-term basis.
Western Canal 2016 BMO 4
Future Monitoring Recommendations - Efforts to identify additional domestic wells to enhance the existing sub-inventory monitoring well network for the development of management objectives in the alluvial aquifer system. Efforts will also be made to identify more wells in all aquifers which meet the criteria developed. Supporting Data – Groundwater Level Hydrographs
Hydrographs on the following pages depict yearly spring groundwater level measurements with established alert levels.
WSE – Water Surface Elevation (feet, above mean sea level) GSE – Ground Surface Elevation (feet, above mean sea level) QM – Questionable Measurement Note: From 2014 to 2016 monthly measurements were taken. The first of the two measurements (March) should be considered the BMO level.
Key Well: 20N01E35C001M
This well has long been a Key Well highlighted in the Butte Basin Water Users Annual Report. The figure below is a hydrograph for an active domestic well 20N01E35C001M, in the central portion of the Western Canal sub-area. The area surrounding this well is characterized as rural agricultural. Agricultural cultivation in this area consists of rice production supported by surface water in normal years and a combination of surface and groundwater in drought years. The well is constructed in the uppermost aquifer system. The groundwater level measurement for this well dates back to 1947. Groundwater levels in this well were monitored on a semi-annual basis until 1991, and on a monthly basis from 1991 to about 1994. Since 1995 this well is typically monitored four times a year during March, July, August and October. From 2014 to 2016, levels were monitored monthly April through October due to drought conditions. The spring to fall fluctuation in groundwater levels averages less than three feet during years of normal precipitation and the same during years of drought. Summer groundwater level monitoring indicates the water table in the upper aquifer rises during summer months due to flood irrigation for rice production producing groundwater level measurements that are higher in the summer than in either the spring or fall. Long-term comparisons of spring-to-spring groundwater levels show almost no change associated with the 1976-77, 1987-92 and 1994 drought periods. Further long-term analysis of spring-to-spring groundwater levels indicates very little change since monitoring began in 1947. Water elevations have been monitored since 1947 at this location and the historical average depth to water, including 2016, is about three feet in the spring and about four feet in the fall below ground surface. No spring measurement was taken in 2012, 2014, 2015 or 2016 due to the well being pumped at the time of monitoring.
Western Canal 2016 BMO 5
WSE – Water Surface Elevation (feet, above mean sea level) GSE – Ground Surface Elevation (feet, above mean sea level)
Western Canal 2016 BMO 6
WSE – Water Surface Elevation (feet, above mean sea level) GSE – Ground Surface Elevation (feet, above mean sea level)
Western Canal 2016 BMO 7
WSE – Water Surface Elevation (feet, above mean sea level) GSE – Ground Surface Elevation (feet, above mean sea level)
Western Canal 2016 BMO 8
WSE – Water Surface Elevation (feet, above mean sea level) GSE – Ground Surface Elevation (feet, above mean sea level)
Western Canal 2016 BMO 9
Monitored Wells without Alert Stages
WSE – Water Surface Elevation (feet, above mean sea level) GSE – Ground Surface Elevation (feet, above mean sea level)
Western Canal 2016 BMO 10
WSE – Water Surface Elevation (feet, above mean sea level) GSE – Ground Surface Elevation (feet, above mean sea level)
Western Canal 2016 BMO 11
WSE – Water Surface Elevation (feet, above mean sea level) GSE – Ground Surface Elevation (feet, above mean sea level)
Western Canal 2016 BMO 12
WSE – Water Surface Elevation (feet, above mean sea level) GSE – Ground Surface Elevation (feet, above mean sea level)
