With the rapid growth of American metropolitan areas, it is essential to plan for the preservation of open space before development occurs on lands which would better be left undeveloped. Although there is a long tradition of parks and open space planning in American cities, planning efforts over the past twenty-five years (since 1960) have not been systematically reviewed and there remains no set standard to guide the planning of regional-scale open space. Two foundations of open space planning are examined: its roles in guiding urban form, and in preserving natural processes in the city. Six case studies of contemporary open space plans and systems elicit the fundamental criteria and decision processes for open space planning.

The seasonal variation in rainfall - runoff response is investigated for about 300 small watersheds throughout the United States. Data from USDA research watersheds were used to define runoff Curve Number for ordered data sets by months. Three major patterns of cyclic variation are found and investigated: 1) distinct and well - defined seasonal variations as typified by forested watersheds in heavy rainfall zones; 2) mildly cyclic variation found typically in meadows and grasslands, and 3) non - cyclic or unidentifiable patterns, including those with insufficient seasonal data. The only pattern that may be present is the well-defined seasonal variation found so far only in forested watersheds. Regional characteristics were found for individual crop types. For the watersheds studied there seemed to be no difference in the variation between crops except for meadow during the summer. Some associated background factors are explored, including long-term and short-term antecedent rainfall.

In the Rocky Mountains, most streamflow results from snowmelt and the demand for water in the western United States makes the value of accurate streamflow forecasting high. Studies have shown that snowpack depletion-runoff relationships have the potential to improve various streamflow forecasting techniques. However, the use of these relationships in streamflow forecasting has been limited by the difficulty in obtaining measures of areal snow cover. The Earth Resources Technology Satellites (ERTS) have shown potential for measuring areal snow cover. Therefore, a study was conducted to determine the feasibility of using ERTS imagery to measure changes in snow cover in east-central Arizona for use in developing snowpack depletion-runoff relationships. Results indicated that, despite some difficulties, ERTS-l imagery could be interpreted for areal snow cover. Also, a highly significant relationship existed between measures o£ areal snow cover from ERTS-l imagery and subsequent runoff during the snowpack depletion period. However, quality ERTS-l imagery cannot presently be obtained frequently enough to be the sole source of data for monitoring changes in areal snow in Arizona. In addition, a delay in obtaining ERTS imagery must be overcome before the data from ERTS imagery can be used for practical applications.