Water Supply and Allocation ToolkitAll fact sheets

Water year 2000 in the Delta: inflow, exports, outflow, and allocations

In water year 2000, an above normal year, 25.24 MAF of river water entered the Sacramento-San Joaquin Delta; the State Water Project and Central Valley Project pumps exported 6.35 MAF of it, 25 percent, and 14.14 MAF flowed to San Francisco Bay above the outflow floor that Water Right Decision 1641 sets for the month and the kind of year. The Delta’s own farms and channels used 0.71 MAF, and net outflow to the Bay was 18.19 MAF, of which 4.11 MAF was the floor itself.

How does 2000 compare with the ten water years before it?

Over water years 1990 to 1999, exports averaged 5.02 MAF a year, 14 percent of inflow. In 2000 the share was 25 percent. On 318 days of the year a standing rule, permit term, or biological opinion held exports below pump capacity while surplus water existed; on 48 days outflow sat at or below the floor, so there was nothing to take without breaking the rule. The most common condition across the year was a rule or permit held exports.

Month by month

MonthInflow (MAF)Exports (MAF)In-Delta use (MAF)Net outflow (MAF)Floor (MAF)Exports, percent of inflowMost common condition
Oct 19990.950.580.110.260.2561.1a rule or permit held exports
Nov 19990.980.570.010.400.2757.8a rule or permit held exports
Dec 19991.150.400.110.640.2834.5a rule or permit held exports
Jan 20001.750.61-0.181.320.2834.8a rule or permit held exports
Feb 20005.750.67-0.335.410.4111.7a rule or permit held exports
Mar 20005.970.560.005.400.449.4a rule or permit held exports
Apr 20001.990.330.041.620.4216.5a rule or permit held exports
May 20001.660.190.101.360.4411.5a rule or permit held exports
Jun 20001.210.470.210.530.4238.5a rule or permit held exports
Jul 20001.480.650.260.570.4943.9a rule or permit held exports
Aug 20001.280.680.230.370.2552.9a rule or permit held exports
Sep 20001.090.660.150.280.1860.6a rule or permit held exports

MAF = million acre-feet.

Where the Delta's inflow went each month, water year 2000 (million acre-feet)0.01.42.84.25.67.0million acre-feetOct Exports: 0.6Oct In-Delta use: 0.1Oct Outflow up to the floor: 0.2Oct Outflow above the floor: 0.0OctNov Exports: 0.6Nov In-Delta use: 0.0Nov Outflow up to the floor: 0.3Nov Outflow above the floor: 0.1NovDec Exports: 0.4Dec In-Delta use: 0.1Dec Outflow up to the floor: 0.3Dec Outflow above the floor: 0.4DecJan Exports: 0.6Jan Outflow up to the floor: 0.3Jan Outflow above the floor: 1.1JanFeb Exports: 0.7Feb Outflow up to the floor: 0.4Feb Outflow above the floor: 5.0FebMar Exports: 0.6Mar In-Delta use: 0.0Mar Outflow up to the floor: 0.4Mar Outflow above the floor: 5.0MarApr Exports: 0.3Apr In-Delta use: 0.0Apr Outflow up to the floor: 0.4Apr Outflow above the floor: 1.2AprMay Exports: 0.2May In-Delta use: 0.1May Outflow up to the floor: 0.4May Outflow above the floor: 0.9MayJun Exports: 0.5Jun In-Delta use: 0.2Jun Outflow up to the floor: 0.4Jun Outflow above the floor: 0.1JunJul Exports: 0.6Jul In-Delta use: 0.3Jul Outflow up to the floor: 0.5Jul Outflow above the floor: 0.1JulAug Exports: 0.7Aug In-Delta use: 0.2Aug Outflow up to the floor: 0.2Aug Outflow above the floor: 0.1AugSep Exports: 0.7Sep In-Delta use: 0.2Sep Outflow up to the floor: 0.2Sep Outflow above the floor: 0.1SepExportsIn-Delta useOutflow up to the floorOutflow above the floor
Each bar is the month’s Delta inflow: exports at the bottom, then the Delta’s own use, then outflow up to the D-1641 floor and outflow above it.

What contractors were told to expect

Contractor classFinal allocation, 2000Final allocation, 1999
SWP Table A100 percent100 percent

Allocations are percentages of contract supply.

How 2000 measures against other supplies

The 6.35 MAF exported in 2000 is 1.4 times California's 4.4 million acre-foot basic apportionment of the Colorado River under the Boulder Canyon Project Act of 1928, the state's other large imported supply. The 14.14 MAF that left the Delta above the floor is 3.1 times the 4.55 million acre-foot capacity of Shasta Lake, the largest reservoir in the state; 79 percent of it passed in three months (Feb, Mar, Apr).

Frequently asked questions

How much water did the Delta pumps export in water year 2000?

6.35 MAF: 2.49 MAF at the Central Valley Project's Jones plant and 3.69 MAF at the State Water Project's Banks plant, which together serve cities and farms on both projects. That was 25 percent of the 25.24 MAF that entered the Delta in an above normal year.

How much Delta water flowed to the ocean in 2000?

Net Delta outflow was 18.19 MAF. Of that, 4.11 MAF was the minimum that Water Right Decision 1641 requires to keep salt water out of the Delta and its intakes, and 14.14 MAF was above that floor, 78 percent of the outflow.

What did project contractors receive in 2000?

The State Water Project's final Table A allocation was 100 percent of contract supply. An allocation is an announcement of the share of contract supply to expect, not a delivered volume.

Explore the year on the toolkit: Delta diversions by month, the constraint calendar, allocation history.

Sources: California Department of Water Resources, Dayflow (CNRA open data, water years 1930 through 2025, as published before 2026-09-18); State Water Resources Control Board, Water Right Decision 1641, Table 3 minimum net Delta outflow; California Data Exchange Center, Sacramento Valley water-year classification; U.S. Bureau of Reclamation, Central Valley Project allocation announcements; DWR, Historical State Water Project Table A Allocations; U.S. Bureau of Reclamation, Boulder Canyon Project Act apportionments and Shasta Lake capacity. Binding-reason day counts for water year 2000: rule or permit 318, no surplus outflow 48, pumps at capacity 0. Definitions: conciseVerbosity Water Supply and Allocation Toolkit, version 1.1 (2026-09-18). Compiled 2026-09-18.