TheImprovement ofTropical and Subtropical Rangelands

REGIONAL RESOUROE ASSESSMENT 77
will have a major influence on the course of the project. Thus, a
resource asse88ID'Bnt must locate sources of surface water such as
springs, streams, lakes, ponds, impoundments, and irrigation works,
as well as average seasonal flows or volumes. Proven subsurface
resources also must be reported by noting the location, depth, and
yield of wells.
Current and JIlstorlcai Land Use
Descriptions of land use are important for at least three reasons.
First, one of the primary purposes of the resource assessment is to
provide an overview of the mix of regional land uses. A comprehensive
description of land uses will provide a general reference and
may suggest functional economic linkages between land uses, such
as irrigated agriculture and animal grazing systems. AJJ.y range improvement
project must consider the relationships that exist between
adjacent land uses.
Second, the land uses and management practices found within
a region give some indication of variations in land capability. For
example, pastures that are used only seasonally may be limited in
their productivity because of cold winters or spring flooding. Such
lands would require sPecial consideration.
Third, some range improvement problems are associated with
specific land uses, such as urban developments and woodcutting in
many places, and should be identified for special treatment.
Like climate, some land uses are difficult to observe. Because
of the ambiguous distinctions between some types of vegetation and
land use (rangeland, for example), they are sometimes mapped together.
A common compromise is to map "land cover," which includes
all observable features that cover the land surface, such as
vegetation, surface water, and various land uses (urban development
or agriculture, for example).
Information on current land use should include maps and deecriptions
of all land uses, settlements, infrastructure (roads, canals,
rail lines, fences, wells, and other watering points), and population
estimates. Descriptions of regional land tenure practices may also
be useful in explaining some land use patterns and management
problems.
The patterns observed now may not be directly attributed to
current land use practices. Historical events or land uses that are
no longer observable may have left profound impacts on the land.