Cover Image
close this book Wells construction: hand dug and hand drilled
View the document Acknowledgments
View the document Introduction
close this folder Section one: Planning
close this folder Chapter 1: Introduction to wells planning
View the document A. Overview
View the document B. The need for adequate water supply
View the document C. Involving the local community
View the document D. Selecting the most appropriate water source
View the document E. Site choice
View the document F. Preventing water contamination
View the document G. Types of wells
View the document H. Well sections
View the document I. Materials
View the document J. Tools and equipment
View the document K. Sinking method
View the document L. Preparation for construction
View the document M. Planning
close this folder Section two: Hand dug wells
View the document Chapter 2: Introduction to hand-dug wells
View the document Chapter 3: Well design
View the document Chapter 4: Supplies
View the document Chapter 5: Lowering and raising workers and equipment
View the document Chapter 6: Digging
View the document Chapter 7: The middle section: overview of lining techniques
View the document Chapter 8: Construction of the middle section
View the document Chapter 9: Construction of the bottom section
close this folder Section three: Drilled wells
View the document Chapter 10: Introduction to drilled wells
View the document Chapter 11: Drilling and casing techniques
View the document Chapter 12: Construction: hand rotary and hand percussion methods
View the document Chapter 13: Construction: sludger method
View the document Chapter 14: Construction: driven and jetted
View the document Chapter 15: The bottom section
close this folder Appendices
View the document Appendix I: Conversion factors and tables
View the document Appendix II: Vegetation as an index of ground water
View the document Appendix III: Uses of dynamite in hand dug wells
View the document Appendix IV: Cement
View the document Appendix V: Leveling and plumbing the mold
View the document Appendix VI: Pipe
View the document Appendix VII: Pumps
View the document Appendix VIII: Water treatment in wells
View the document Appendix IX: Rope strength
View the document Glossary
View the document Annotated bibliography

D. Selecting the most appropriate water source

When the community has decided that more and better water is needed, it will be necessary for them to decide what kind of source is possible and will best suit their needs. A well is not always the most appropriate water source in a particular locale. Their goal is to find the cheapest, most reliable way to provide the needed amount of clean water.

Here are the chief potential sources of water listed in their approximate order of preference based on cost, quality of water, need for equipment and supplies:

• Springs - If there are year-round springs nearby, they can usually be developed to supply clean water. This water can often be conveyed through pipes without the expense of pumps or water treatment. Springs can most often be found in hilly or mountainous regions (see Fig. 1-1):

• Wells - Because there is water at some depth almost everywhere beneath the earth's surface, a well can be sunk (using the appropriate technique), almost anywhere. The water that comes into the bottom of a well has filtered down from the surface and is, in most cases, cleaner than water that is exposed on the open ground;

• Rainwater - Collection and storage of rainwater may provide another source where surface and underground water supplies are limited or difficult to reach. Normally, except in the rainiest regions, rainwater will not supply all the water needs of a locale; however, as a supplement, it can be collected from roofs or protected ground run-off areas, and stored in covered cisterns to prevent contamination.


FIG. 1-1. SPRING LOCATION

• Surface water - Streams, rivers, and lakes are all commonly used as sources of water. Although no construction is needed to enable them to supply water, the quality of the water is almost always poor. Only clear mountain streams flowing from protected watersheds could be considered as fit for human consumption.