Water-retaining barrier and method of construction

A water retaining barrier providing a medium for supporting plant life in an arid or semi-arid land region having a ground surface, said barrier being disposed in a trench in the land region, said barrier comprising:

• a first layer composed of pieces of rock, said first layer being porous and being in contact with the native soil;
• a porous second layer of at least one material selected from at least one of sand and gravel, said second layer being less porous than, and overlying, said first layer;
• and
• a porous third layer containing soil which favors plant growth, said third layer being less porous than, and overlying, said second layer and having an exposed upper surface, wherein
• the porosities of said second and third layers differ from one another by an amount which impedes transport of soil from said third layer into said second layer;
• said upper surface of said third layer is at substantially the same level as the ground surface adjacent the trench;
• a first surface portion of the ground surface adjacent one side of the trench slopes downwardly toward the trench;
• and
• said barrier further comprises a first layer of substantially nonporous material disposed upon the first surface portion and extending to the trench.

A water retaining barrier providing a medium for supporting plant life in an arid or semi-arid land region having a ground surface, in combination with two sidewalls, said barrier being disposed on the ground surface and having two sides extending upwardly from the ground surface, and said two sidewalls each resting on the ground surface and covering a respective side of said barrier, said barrier comprising:

• a first layer composed of pieces of rock, said first layer being porous and being in contact with the native soil;
• a porous second layer of at least one material selected from at least one of sand and gravel, said second layer being less porous than, and overlying, said first layer;
• and
• a porous third layer containing soil which favors plant growth, said third layer being less porous than, and overlying, said second layer and having an exposed upper surface, wherein
• the porosities of said second and third layers differ from one another by an amount which impedes transport of soil from said third layer into said second layer.

A water retaining barrier providing a medium for supporting plant life in an arid or semi-arid land region having a ground surface, said barrier being disposed on native soil of the region, said barrier comprising:

• a first layer having a thickness and composed of pieces of rock, said first layer being porous and being in contact with the native soil;
• a porous second layer having a thickness and containing of at least one material selected from at least one of sand and gravel, said second layer being less porous than, and overlying, said first layer;
• and
• a porous third layer having a thickness greater than the thickness of said second layer and containing soil which favors plant growth, said third layer being less porous than, and overlying, said second layer and having an exposed upper surface, wherein
• the porosities of said second and third layers differ from one another by an amount which impedes transport of soil from said third layer into said second layer.