If you're thinking about buying a retractable awning, consider the value, longevity and cost. Purchasing a retractable deck awning is a big investment. While smaller, less-expensive awnings start at around $500, larger, higher-quality awnings can cost as much as $2,000 or more. Before you make the decision to buy a retractable awning, you should learn as much as possible about their benefits and drawbacks. Here are the top three pros and cons to consider.
Drainage basin (catchment area) is the area which supplies a river system, lake or reservoir with water. The whole area consists of smaller sub-catchments supplying tributaries of the main ri-ver and direct catchments, which drain straight into a lake or main river (Box 3.1).ts purpose is to co-nvey excess water from a drainage basin, which will include the products of weathering and addi-tional loads of solutes produced by man. This pro-perty makes a drainage basin an integrator and its operation is reflected in the quantity and quality of the river run-off.
In human geography, a catchment area is the area from which a city, service or institution attracts a population that use their services. For example, a school catchment area is the geographic area from which students are eligible to attend a local school. Supermarkets, on the other hand, have a much lower density, with catchment areas of several neighborhoods (or several villages in rural areas). 2  This principle, similar to the central place theory, makes catchment areas an important area of study for geographers, economists, and urban planners.