Drought Update: 05/08/2002

Rainstorms during Mach and April have helped to green up vegetation, improve stream flows temporarily, and provide the illusion that the State's water supply situation has improved dramatically. However, two months of rainfall at near-normal levels cannot erase the rainfall deficit that has accumulated from 15 out of the last 19 months having significantly below normal rainfall. (Think of getting only 2/3 of your salary for 15 months - it will take more than two months at your usual salary to pump your bank account back up to normal.)

From October through April, precipitation should be recharging the shallow groundwater system. However, since rainfall during this period in 2001-2002 was at record lows, very little recharge occurred and ground water levels are still very low. These levels normally peak in April and May and then decline from May thought October, as evapotranspiration from growing plants pulls water out of the shallow groundwater system. We are starting the summer with near-record low shallow groundwater levels. Therefore, even with normal amounts of precipitation now, we would still have record low, shallow groundwater levels this summer. Without a long period of higher than normal rainfall, the next real opportunity for recharging shallow groundwater will be in the fall of 2002.

In New Jersey the highest stream flows occur during late fall through spring, November through May. Throughout much of this period in 2001 -2002, the majority of New Jersey's streams have been at or near record low levels due to record low rainfall. With each rain event stream flows rise but quickly fall to levels far below normal for this time of year. Even with the current rains, stream flows are still significantly below normal for his time of year. Stream flows are not expected to return to normal until the shallow groundwater systems recover to normal levels.

The effect of a rainstorm on the drought can vary tremendously depending on how fast and hard the rain falls, and for how long the rain continues. A long, light rain allows more water to soak into the ground and is therefore good for ground water recharge, long term stream flow, and plant growth. Short, hard rains dump so much water at once that it can't soak into the ground, resulting in more runoff. Runoff is good for filling reservoirs, but does not improve groundwater and only temporary improves stream flow. Therefore, even though reservoir levels have been rising with the rainfall in March and April, we must still conserve as much water as possible, until both shallow groundwater and stream flows return to near normal levels.

Past Drought Updates