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RESOURCE PLANNING Effective solutions to urban erosion and sediment prob- lems begin with planning. Broad resource plans developed by local units of government and enforced through land use or zoning regulations can, if properly prepared and implemented, avoid development in areas where high erosion hazards exist. Resource plans should control and guide urban growth so that developments do not take place haphazardly and are not harmful or wasteful of resources. Adequate planning will reduce or eliminate many urban problems such as erosion, sediment, flooding and wetness. These kinds of problems are costly, unhealthful, wasteful, and contribute to deterioration of environmental quality. Planning to solve and control these problems at the outset will help provide for orderly growth and development while safeguarding the resources essen- tial to a satisfactory environment. Resource plans must identify areas unsuitable for in- tensive development and utilize these areas for open space or recreational uses. Intensive construction activities should not be planned for sites having severe soil limitations, geologic hazards and danger from flooding. DEVELOPMENT PLANS Subdivision plans or other plans covering portions of the overall city plan are more specific in nature and usually require considerably more detailed information and interpretations for use in planning. Such detailed information would determine the suitability of the site for the intended uses. The information would also help in the planning of conservation treatment needed to protect the areas during development from damages by flooding, erosion, sediment or a high water table. If a program for erosion control is considered early in the planning stage and made part of the development plan, problems of soil erosion, runoff, and sedimenta- tion usually can be reduced. Detailed information on soils, topography and geologic and hydrologic conditions should be obtained for the site. Special attention should be given to identify and evaluate problems that may cause serious erosion dur- ing construction. Runofffrom the site, as well as runoff from the watershed above, must be controlled and dis- posed of safely. Preventi ve measures are needed to avoid erosion and sediment damages to downstream property. Consider fitting the buildings and streets to the natural topography. This reduces the need for excessive cuts and fills. The cluster method of development is an al- ternative that can be used to keep steep areas undis- turbed. Existing trees, if saved, can play an important role in residential development. They can reduce de- velopment cost and help control erosion. Trees can enhance home sites and contribute to the aesthetic ap- peal of the community. These are some concerns that need to be evaluated during planning and design to get erosion control into the site development plan. There are alternative ways to control erosion and sedimentation on almost all sites. The method selected generally is based on such factors as time of year that construction will take place, builders' preference, ex- tent of grading, and amount of cover on the land. On most sites, it will take a combination of methods such as fitting the development to the topography, limiting the area exposed at one time, limiting the amount of exca- vation, and applying appropriate erosion control mea- sures. SOIL SURVEYS CAN HELP Soil surveys can be useful in planning for erosion and sediment control. The surveys contain soil maps and soil descriptions. The soil maps are imprinted on aerial photographs. They identify soils on the ground in relation to streams, roads, and other landscape features. Each soil is described in detail. Soil characteristics and properties such as texture, slope, permeability, erodi- bility, wetness, and depth to rock are given. F1ood- prone soils, high shrink-swell soils, and other soils that have problems for specific uses are identified. The soil survey has useful information for planning. It does not eliminate the need for on-site investigations for specific uses. Published soil surveys are available for many areas of Colorado. Copies can be obtained from the Soil Con- servation Service office. Where surveys are not avail- able, new mapping may be requested through local soil conservation districts. HYDROLOGIC INFORMATION The effect of urbanization on the water regimen has long been recognized. Investigations to evaluate the factors involved have been going on for over 35 years. 6