Droughts
Droughts
Droughts refers to a deficiency in precipitation over an extended period, usually a season or more, that results in water shortages that can cause adverse impacts on vegetation, animals and/or people.
Droughts are a normal and recurrent feature of climate that occurs in virtually all climate zones, and usually presents as an aberration from normal climatic conditions. Human factors, including water demands and water management, can exacerbate the impacts of a drought on a region.
Drought events are typically slow onset hazards but can, over time, have very widespread damaging affects to crops, public water supplies and recreational activities. Long term, persistent droughts can incidentally increase an areas risk to wildfires.
Drought events are typically slow onset hazards but can, over time, have very widespread damaging affects to crops, public water supplies and recreational activities. Long term, persistent droughts can incidentally increase an areas risk to wildfires.
Drought Classifications
Meteorological
Usually defined based on the degree of dryness (in comparison to some "normal" or average) and the duration of the dry period. Drought onset generally occurs with a meteorological drought.
Hydrological
Usually occurs following periods of extended precipitation shortfalls that impact water supply (i.e. stream flow, reservoir and lake levels, ground water), potentially resulting in significant societal impacts.
Agricultural
Links various characteristics of meteorological (or hydrological) drought to agricultural impacts such as:
- Precipitation Shortages
- Reduced Ground Water
- Reservoir Levels Needed for Irrigation
- Soil Water Deficits
Drought Monitoring
National Integrated Drought Information Systems
Droughts are currently monitored by the National Integrated Drought Information Systems (NIDIS), a collaborative effort lead by the National Oceanic and Atmospheric Administration.
The NIDIS provides daily drought monitoring reports along with seasonal drought outlooks products. Drought forecast products are produced in 6 month increments showing the potential for development and persistence of drought conditions.
Partners of the NIDIS include the U.S. Department of Agriculture, U.S. Geological Survey, U.S. Army Corps of Engineers and several academic agencies.
View the National Integrated Drought Information System and the Palmer Drought Severity Index.
Palmer Drought Severity Index
The Palmer Drought Severity Index (PDSI) is a measure of droughts developed by Wayne Palmer that is widely used in the United States for tracking moisture conditions. The PDSI is defined as "an interval of time, generally in months or years in duration, during which the actual moisture supply at a given place rather consistently falls short of the climatically expected or climatically appropriate moisture supply."
The range of PDSI is from -4.0 (extremely dry) to +4.0 (excessively wet), with the central half (-2.0 to +2.0) representing the normal or near normal conditions.
The PDSI is best used for long-term measurements of drought. For short-term (week-to-week) measurements, it is more useful to use the Crop Moisture Index (CMI), also developed by Wayne Palmer.
View the Crop Moisture Index
Water Conservation
Water conservation is becoming an essential practice in all regions, even in areas where water seems abundant. In addition to possibly saving money on utility bills, water conservation helps prevent water pollution in nearby lakes, rivers and local watersheds.
Conserving water may also help extend the life of your septic system by reducing soil saturation, and reducing any pollution due to leaks. Overloading municipal sewer systems can also cause untreated sewage to flow to lakes and rivers. The smaller the amount of water flowing through these systems, the lower the likelihood of pollution.
Want to learn more about water conservation and things you can do at home? Click on the links below:
Conserving water may also help extend the life of your septic system by reducing soil saturation, and reducing any pollution due to leaks. Overloading municipal sewer systems can also cause untreated sewage to flow to lakes and rivers. The smaller the amount of water flowing through these systems, the lower the likelihood of pollution.
Want to learn more about water conservation and things you can do at home? Click on the links below:
Drought Safety
Drought
Strategies for drought preparedness focus mainly on water conservation. Make these practices a part of your daily life and help preserve this essential resource.
Visit the Water Conservation section above to learn simple practices to help reduce water waste.
Indoor Water Conservation Tips Prior to a Drought
GENERAL
- Repair dripping faucets by replacing washers. One drop per second wastes 2,700 gallons of water per year.
- Check all plumbing for leaks and have any leaks repaired by a plumber.
- Retrofit all household faucets by installing aerators with flow restrictors.
- Install an instant hot water heater on your sink.
- Insulate your water pipes to reduce heat loss and prevent them from breaking.
- Choose appliances that are more energy and water efficient.
- Consider purchasing a low-volume toilet that uses less than half the water of older models. Note: In many areas, low-volume units are required by law.
- Install a toilet displacement device to cut down on the amount of water needed to flush. Place a one-gallon plastic jug of water into the tank to displace toilet flow (do not use a brick, it may dissolve and loose pieces may cause damage to the internal parts). Be sure installation does not interfere with the operating parts.
- Replace your showerhead with an ultra-low-flow version.
- Kitchen sink disposals require a lot of water to operate properly
Outdoor Water Conservation Tips Prior to a Drought
GENERAL
- Check your well pump periodically. If the automatic pump turns on and off while water is not being used, you have a leak.
- Plant native and/or drought-tolerant grasses, ground covers, shrubs, and trees. Group plants together based on similar water needs.
- Install irrigation devices that are the most water efficient for each use, such as micro and drip irrigation, and soaker hoses.
- Use mulch to retain moisture in the soil. Mulch also helps control weeds that compete with landscape plants for water.
- Avoid purchasing recreational water toys that require a constant stream of water.
- Avoid installing ornamental water features (such as fountains) unless they use re-circulated water.
- Consider rainwater harvesting where practical.
- Contact your local water provider for information and assistance.
- Position sprinklers so water lands on the lawn and shrubs and not on paved areas.
- Repair sprinklers that spray a fine mist.
- Raise the lawn mower blade to at least three inches or to its highest level. A higher cut encourages grass roots to grow deeper, shades the root system, and holds soil moisture.
- Plant drought-resistant lawn seed. Reduce or eliminate lawn areas that are not used frequently.
- Avoid over-fertilizing your lawn. Applying fertilizer increases the need for water. Apply fertilizers that contain slow-release, water-insoluble forms of nitrogen.
- Put a layer of mulch around trees and plants to reduce evaporation and keep the soil cool.
- Invest in a weather-based irrigation controller—or a smart controller.
- Install a new water-saving pool filter. A single back flushing with a traditional filter uses 180 to 250 gallons of water.
- Cover pools and spas to reduce evaporation of water.
Observe any state or local water restrictions during periods of drought. Also Consider the following tips:
BATHROOM
- Avoid taking baths—take short showers—turn on water only to get wet and lather and then again to rinse off.
- Avoid letting the water run while brushing your teeth, washing your face or shaving.
- Operate automatic dishwashers only when they are fully loaded. Use the "light wash" feature, if available, to use less water.
- Clean vegetables in a pan filled with water rather than running water from the tap.
- Store drinking water in the refrigerator. Do not let the tap run while you are waiting for water to cool.
- Avoid rinsing dishes before placing them in the dishwasher; just remove large particles of food. (Most dishwashers can clean soiled dishes very well, so dishes do not have to be rinsed before washing)
- Avoid using running water to thaw meat or other frozen foods. Defrost food overnight in the refrigerator or use the defrost setting on your microwave oven.
- Operate automatic clothes washers only when they are fully loaded or set the water level for the size of your load.
Outdoor Water Conservation Tips While in a Drought
CAR WASHING
- Use a commercial car wash that recycles water.
- If you wash your own car, use a shut-off nozzle that can be adjusted down to a fine spray on your hose.
- A heavy rain eliminates the need for watering for up to two weeks. Most of the year, lawns only need one inch of water per week.
- Check the soil moisture levels with a soil probe, spade or large screwdriver. You don't need to water if the soil is still moist. If your grass springs back when you step on it, it doesn't need water yet.
- If your lawn does require watering, do so early in the morning or later in the evening, when temperatures are cooler.
- Water in several short sessions rather than one long one, in order for your lawn to better absorb moisture and avoid runoff.
- Use a broom or blower instead of a hose to clean leaves and other debris from your driveway or sidewalk.
Additional Resources:
Would you like to learn more about drought? Visit these additional sites: