Renewable Resource
- something valuable nature keeps supplying on its own
(e.g. rain renews water supply)
More precious than oil, yet routinely wasted, some say water is the world's most pressing resource issue. Fresh water is the reason you live where you do … even if you live in an arid climate in the mountains or on a leeward coast, irrigation (water pipelines) carries fresh water to your town. Yet water policies (laws & guidelines) in most nations do not protect this vital resource.
How scarce is water? In the last century world wide water use rose sixfold — more than double the rate population grew — and use of water continues to grow rapidly as agricultural, industrial, and domestic demand increases.
Fig.1 shows that 41% of the world – 2.3 billion people – lives in river basins with "water stress," meaning that water supply is less than 1,700 m³/year per person & water shortages occur often.
What do we use all that water for?
Fig.3 above shows where the world’s water goes. Most of it goes to farms to keep the plants and animals we eat alive and well.
Why are we running out? We waste it! Agriculture uses most of our water, but 60% of it never reaches the crop and is lost to evaporation and runoff. We also take water from ancient aquifers that don’t replenish fast and sometimes we “overdraft” water that should be going to streams and aquatic ecosystems. Plus, we pollute our water with nitrates, pesticides, and industrial chemicals – in some places it’s so bad even industries can’t use it.
How long before the water planet goes dry? In the last 20 years in the US there were 8 major water shortages – one cost nearly 40 billion dollars. Now, 36 states are on the federal list of expected water shortage areas. Even though the US has many dams to store water, it is still being used up faster than it can be replenished. Now, in countries like India, farmers have stopped farming and are selling the water on their land to city dwellers and industries. Such “water markets” are also becoming popular in arid places in the US and Australia. That’s not a solution, though. New technologies for water use, conservation, & re-use are! / Where Does Hawai‘i Get Its Fresh Water?
Home Catchment
About 60,000 people in Hawai‘i depend on rain-water for most, if not all, of their house-hold water needs. Some use a pool & pipe system to catch it.
However, most of us get water from island aquifers. Rain falls on Hawaii's forested mountaintops & trickles down through volcanic rock to become the ground water for the next generation. Our tap water is rain that fell 25 years ago!
Will Hawai‘i Have a Problem?
Some say yes, some say no. Hawai‘i water managers say drinking water supplies will be okay for 20 years, but a federal report says Hawai‘i will have shortages within 10 years.
"If people are willing to pay to make fresh water out of ocean water, it certainly can be had," says one official.
Honolulu plans to build a 5 million-gallons-per-day desalinization plant. But can this keep up to problems in the future? Environmental experts say global warming, climate change & severe storms will make it hard!
NAME: CLASS:
WILL THERE BE ENOUGH WATER:
QUESTIONS FOR GROUP DISCUSSION
1. Where does the fresh water in your home come from? Think of at least 3 things you use water for at home, and 3 sources where you probably get that water.
2. According to this reading, what 3 things do we use fresh water for worldwide? What percentages of water does North America’s use? How does this compare to how other continents use water?
3. According to this reading, how do we waste water?
4. Many governments let farmers pay much lower prices for their water. Why do they do this? What are the positive and negative consequences of this?
5. Drip irrigation systems on farms cut water use 30-70% and increase crop yields 20-90%. Although the use of drip irrigation has grown more than 50-fold over the last 20 years, it is still used in only 1% of the world's irrigated areas. Why do you think this is so? What could be a solution to this problem?
6. Imagine you are going to speak to government officials at a public forum about what they should do about water resource issues. Think up at least 3 things you think should be done to solve water supply problems in Hawai‘i &/or around the world.
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Science in Hawai‘i: Nā Hana Ma Ka Ahupua‘a – A Culturally Responsive Curriculum Project
Retrieved & adapted 11/23/03 from: http://earthtrends.wri.org/features/view_feature.cfm?theme=2&fid=17; and 10/6/05 from www.ctahr.hawaii.edu/ctahr2001/CTAHRInAction/Feb_02/TMacomber.html & http://starbulletin.com/2003/07/11/news/story3.html