More of the earth's surface is covered by water than by land.
More of the earth's surface is covered by water than by land. About 97.5% of that water is found in the oceans, saline lakes and brackish estuaries. Fresh water makes up only about 2.5% of the total and almost three-quarters of that is tied up in glaciers, permanent snow cover and permafrost which is unavailable for human needs. Nevertheless, the approximately 0.75% of the total water on earth that is important to human beings as a potential source of domestic, industrial and agricultural water amounts to a whopping 10,665,000 cubic kilometers.
The part called run-off (precipitation over land, minus evaporation over land) is what is actually available to us and that amounts to around 47,000 cubic kilometers annually. Worldwide that breaks down to about 7,000 cubic meters per capita annually. That's still an enormous amount of water. You know those big tank trucks that haul fuel for gas stations? Theoretically there is an amount equal to 300 of those full of water for every person on the planet each year. I say theoretically because we still have to capture it before it flows to the ocean. I apologize for all the big numbers, but the point is; there is a lot of water out there.
In spite of these enormous amounts of water, I've seen many news reports about water shortages. About half of China's 600 cities are short of water. In California the cities are buying water from the farmers. The Colorado River runs dry before it reaches the ocean. Drought in Central America has caused food shortages and a need for emergency aid to millions of people. Many Central American cities regularly suspend water service and racion water regularly because of drought. San Jose, Costa Rica rations water every dry season. Within 40 kilometers of Dominical the communities of Hatillo, San Agustin, Uvita, La Reina, San Rafael de Balzar, La Rivera de Concepción and Barú regularly experience water shortages even in the rainy season. Hey, what's going on here? I thought it was supposed to rain a lot in the tropics?
I'm afraid I don't have the answer to that one, but I do have a few ideas. When rain falls on bare ground it runs-off quickly into the streams and rivers, often washing away a layer of topsoil. When it falls on a forest, the rain is absorbed and slowly released, just like pouring water on a sponge. I love walking in the rain forest during a downpour. When it begins you hear the raindrops hitting the canopy, but several minutes elapse before the moisture filters through all the layers of foliage down to ground level. You never actually get rained on; but you get soaked anyway. The atmosphere is 100% humidity and most of the water is absorbed and held within the biomass. There is less run-off and more filtration into deep soil layers. That water is then released slowly, over a period of months.
When I first came to Hacienda Barú in February of 1972, this entire area was drier. There was less forest and more farmland and overgrazed pastures. I didn't begin a program of restoring natural habitat on former pasture land until 1979. Running out of water during the dry season was just part of life. Usually our domestic water source quit flowing around early February and didn't return until late April. There was a lot of variation from year to year. The driest year I remember was 1982-83. The rains stopped in late October of 1982 and didn't return until May of 1983.
The water source that fed our household system dried up in late December and didn't start flowing steadily again until late June. To cope with the situation we hauled drinking water from San Isidro in five gallon containers. House cleaning and toilet flushing water came from the Barú River in 55 gallon drums. We took the girl who worked in the house to the river each day, with a basket full of clothes, to do laundry. Our afternoon bath in the Barú River was a cherished family ritual. Dominical didn't have any water either and most of the town, about 10 people, would meet us at 4:00 PM at the river crossing (there wasn't a bridge in those days.) The otters got to know us too and would often show up to watch everyone bathe. During the dry season of 1983 the flow of the Barú got so low that we were afraid it would go dry.
In 1981 I began keeping rainfall records. Later the Costa Rican National Meteorological Institute installed an official weather station at Hacienda Barú. Get ready! Here come some more numbers. Between 1981 and 2002 the average annual rainfall was 4,406 mm (14 ft., 9 ½ in.) That's about as high as the peak of the roof of a small single-story house in Costa Rica. The year 1983 held the record low of 3,882 mm for 11 years up until 1994 when the total for the year was only 3,673 mm. Then, in 1997 it dipped more than one meter to 2,610 mm. Those years were all affected by the El Niño phenomenon which inevitably brings drier conditions.
The surprising thing is that 2001 only had 3,484 mm and 2002 had only 3,250 mm. That means that the four driest years since 1981 have all occurred since 1994. I'm not a statistician, but this definately seems like a trend.
According to the latest report of the Intergovernmental Panel on Climate Control (IPCC,) we can expect more extremes in weather in the future. Dry years will be dryer and wet years will be wetter, not counting El Niño events. We can only guess what this means in terms of future weather, but in terms of our daily lives it means we need to do some serious thinking about the water situation.
We don't want to run out of water in the middle of the high tourist season, which coincides with the driest part of the year.
A lot of the businesses in this zone have drilled wells as a solution. Wells aren't the answer. The more of them we drill, the more they lower the water table. When it gets too low salt water seeps in. The wells in this area aren't pumping from an aquifer. They are pumping surface water that has filtered down. That means that a severe drought will cause wells to go dry temporarily. This happens to some of the wells in the region every year. Another problem with these shallow wells is contamination. Where there are a lot of septic tanks in a small area there is more danger.
For those who live in small communities with their own water system it would be good to find out where your water originates. If there isn't a lot of forest around the source, you might want to think about organizing your community to plant trees and protect the area so that forest can grow back naturally. The more area covered by the forest, the better. A big sponge holds more water than a small one. Granted this is a long range solution, but visible results can be seen in less than 10 years. Hacienda Barú doesn't have any water problems today. But we have a lot more forest than we had in 1983. As a matter of fact, the entire area between the Savegre River and the Terraba River can boast more forests and more water now than 20 or 30 years ago; but there are also more people and everyone's piece of the pie is getting thinner. Many community water systems quit flowing each dry season and many show signs of getting worse.
Any attempt we can make to restore rain forest will improve our dwindling water supply while bringing numerous other benefits. The Path of the Tapir Biological Corridor (PTBC) is a project of ASANA, a local environmental group. The primary goal of the corridor is to restore forests and other natural habitat to significant areas between the Térraba River to the south and the Savegre River to the north. Dominical is right in the middle. The primary focus is on connecting all the isolated forest patches to one another. On a larger scale the southern end of the PTBC will connect to the Osa Biological Corridor and the northern end to the Inter Oceanic Biological Corridor. The Inter Oceanic Corridor will then connect the entire network to the Mesoamerican Biological Corridor which stretches from Mexico to Panama.
A large part of the PTBC strategy revolves around stopping deforestation and protecting water sources. We are on the verge of convincing the Environmental Ministry to declare the entire corridor off limits to logging. A new organization called ACODESFIC, representing 19 communities within PTBC, has been formed in response to water shortages and unrestrained issuing of logging permits. Because of pressure from ASANA and ACODESFIC, the Environmental Ministry has ordered the three regional offices, with authority to issue logging permits within the PTBC, to temporarily suspend all permits until a permanent solution can be found.
I feel confident that the entire corridor, all the land between the Savegre River and the Térraba River 100 kilometers to the south, will be declared a water protectorate and therefore not permissible for logging. If you know anybody who wants to buy forested land here and exploit the timber, tell them to go to a different region. Better yet, tell them to go to a different country.
These restrictions won't apply to reforested lumber, only to natural forests. Promoting commercial planting and sustainable harvesting are an important part of ASANA's plan for the corridor. Another group, Tropical Forestry Initiative is also working along these lines. Former pasture land can be planted to mixed species stands of native trees that simulate natural forests and provide wildlife habitat. Then they can be harvested in such a manner that the forest is never clear-cut. Trees that are removed are replaced. Formerly abundant lumber species, now locally extinct are being reintroduced. This is one viable economic alternative to cattle ranching and rice farming.
Ecological tourism is another alternative that is already proven and has a rapidly expanding market. As the Path of the Tapir Biological Corridor advances, wildlife populations increase and more species of wildlife migrate into the area. This is already happening. There have been reliable sightings of pumas, brocket deer, white-lipped peccary and spider monkeys in areas where they haven't been seen for years. Within Hacienda Barú National Wildlife Refuge we have seen movements of wildlife into parts of the reserve which were formerly pasture and rice fields. Increased wildlife populations in the lowlands have even attracted poachers, where in years past we only had to worry about illegal hunting in the upper portions of the hacienda. With the Path of the Tapir Biological Corridor everyone wins, but the loggers.
Most of the facts and figures in this article came from The World's Water 2000-2001 by Peter H. Gleick, published by Island Press and State of the World 2000 from Worldwatch Institute. On the subject of climate change I recommend the web site www.ipcc.ch.
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