Alternative Annual Report
2-009.01 NILES CONE
2024 (OCT. 2023 - SEP. 2024)
A Groundwater Extraction
Total Groundwater Extractions (AF)
16,459
Water Use Sectors
10,495
2,077
54
0
0
0
3,832
"Non-Revenue Water," "Desal to SF Bay," and "ARP" were added as Water Use Sectors to account for water that could not be appropriately categorized under SGMA water use sectors. "Non-Revenue Water" is the amount of water supplied to the ACWD distribution system less the summation of meter readings for which customers were billed. Non-Revenue Water includes non-billed consumption (fire flows, distribution system flushing, etc.) plus real and apparent losses. "Desal to SF Bay" is brine and brine dilution water discharged from the Desalination Facility as wastewater and discharged to San Francisco Bay. "ARP" is the Aquifer Reclamation Program. Groundwater classified under "ARP" is water extracted to improve basin water quality, but is not supplied to the Desalination Facility for potable reuse.
B Groundwater Extraction Methods
Meters
16,458
Direct
Other
Metered extractions include ACWD Wellfields, ACWD to Desalination Facility, ACWD ARP Wells, and non-ACWD Owned/Operated Wells (except one low-producing well).
ACWD?s Replenishment Assessment Act requires metering of all wells except for certain low producing wells. Therefore, all but a small amount of groundwater pumping is metered; see Table 4 in the 2025 SGMA Annual Report for more detail.
Electrical Records
0
Land Use
0
Groundwater Model
0
Other
1
Estimate
Other
The amount extracted was estimated by the run time and past history of metered production rates.
The amount extracted was estimated by the run time and past history of metered production rates.
C Surface Water Supply
Total Surface Water Supply (AF)
41,767
Methods Used to Determine
In ACWD's SGMA Annual Report, Surface Water Supply is divided among "For Managed Aquifer Recharge" and "Direct to Distribution System in Lieu of Groundwater Extraction" supply categories. "For Managed Aquifer Recharge" supplies include measured flows that ACWD impounds and/or diverts for groundwater recharge and are directly input to ACWD's groundwater model, NEBIM. Annual reports in previous years had included an estimate for non-metered sources to recharge ponds (direct rain and runoff from fringe lands), which are not directly measured. These non-gaged forms of recharge are accounted for in NEBIM through simulated processes such as deep percolation, small watershed flows, and surface water-groundwater interactions. SWP and SFPUC RWS supplies are imported into ACWD?s service area through the South Bay Aqueduct (SBA) and Hetch Hetchy Aqueduct, respectively. Local supplies include groundwater from the Niles Cone Groundwater Basin, desalinated brackish groundwater from portions of the groundwater basin previously impacted by saltwater intrusion, and surface water from the Del Valle Reservoir. The primary source of recharge for the Niles Cone is from percolation of runoff from the Alameda Creek watershed and, to a lesser degree, direct stormwater capture. A portion of the District?s SWP supplies are also used for supplemental groundwater recharge. Infiltration of rainfall and applied water also contribute to local groundwater recharge.
Water Source Types
0
6,952
0
13,178
21,601
36
0
0
D Total Water Use
Total Water Use (AF)
58,225
Methods Used to Determine
Water Use is metered or gaged by Agency and/or Water Source Type. ACWD sources include local surface water from the Alameda Creek Watershed (measured by stream gage), extracted groundwater (with non-ACWD wells metered through the Replenishment Assessment Program), SWP (metered), SFPUC (metered), Lake Del Valle (metered), and Semitropic Water Storage District (metered). Local surface water from the Alameda Creek Watershed, as well as some SWP and Semitropic Water Storage District water, was used for managed aquifer recharge, which is recovered as groundwater pumping and other groundwater demands. Therefore, the numerical Total Water Use is not a net water supply value. Water Use by Non-ACWD Owned/Operated Wells and the City of Hayward Distribution System (via SFPUC) are also metered.
Water Source Types
16,459
13,178
36
0
28,552
Includes water imported from the SWP (6,952 AF), SFPUC (11,093 AF), Lake Del Valle (9,329 AF), Semitropic Water Storage District (0 AF), and the City of Hayward Distribution System via SFPUC (1,179 AF). Note that 36 AF of recycled water from the City of Hayward Distribution System is accounted for in the 'Recycled Water' field (column G). Note that some SWP water was used for managed aquifer recharge, which is recovered as groundwater pumping and other groundwater demands.
Water Use Sectors
34,411
5,000
54
0
13,178
0
5,582
"Non-Revenue Water" (2,498 AF), "Desal to SF Bay" (2,969 AF), and "ARP" (114 AF) were added as Water Use Sectors to account for water that could not be appropriately categorized under SGMA water use sectors. "Non-Revenue Water" is the amount of water supplied to the ACWD distribution system less the summation of meter readings for which customers were billed. Non-Revenue Water includes non-billed consumption (fire flows, distribution system flushing, etc.) plus real and apparent losses. "Desal to SF Bay" is brine and brine dilution water discharged from the Desalination Facility as wastewater and discharged to San Francisco Bay. "ARP" is the Aquifer Reclamation Program. Groundwater classified under "ARP" is water extracted to improve basin water quality, but is not supplied to the Desalination Facility for potable reuse.
E Change in Storage
Principal Aquifer Name |
Change In Storage (AF) |
|---|---|
| AHF Aquifer | 685.0 |
| Newark Aquifer | -2183.0 |
| Centerville Aquifer | -145.0 |
| Fremont Aquifer | 1.0 |
| Deep Aquifers | -79.0 |
| Total | -1721.0 |
Method used to calculate change in storage
Simulation results from ACWD's groundwater model, NEBIM, for WY 2023/24 indicates modest decreases in storage in each of the aquifers except the AHF Aquifer. Most of the decrease was simulated to have occurred in the Newark Aquifer, which has a phreatic surface in the greater forebay area. The AHF Aquifer, which also has a phreatic surface (adjacent to the hillsides), simulated a slight increase in storage in WY 2023/24 (corresponding with the increase in water levels discussed above). The decrease in storage in WY 2023/24 compared with WY 2022/23 was due primarily to relatively lesser amount of rainfall experienced, which generated a resulting decrease in amount of natural recharge. As a result of the wet conditions during WY 2023/24 and ACWD?s ongoing managed aquifer recharge efforts, piezometric heads in both the AHF and BHF sub-basins remained in their respective operating ranges.
