Nutrient release from three small watersheds in Oregon's Coast Range was monitored for 2 years before and 2 years after logging. One watershed, Flynn Creek (203.14 ha), served as an untreated control. Deer Creek (303.32 ha) was patch‐cut. No change in the concentration or yield of nitrate nitrogen, phosphorus, or potassium was observed after logging. Needle Branch (70.68 ha) was clear‐cut and burned. Maximum nitrate nitrogen concentrations increased from 0.70 to 2.10 mg/1. Nitrate nitrogen concentrations returned to prelogging levels by the sixth year after logging. Yield of nitrate nitrogen increased from 4.94 to 15.66 kg/ha the first year after treatment. Potassium concentrations increased markedly after burning from about 0.60 to 4.40 mg/1 but returned to prelogging levels within 2 months. Phosphorus concentrations were unchanged. These changes pose no threat to aquatic or terrestrial productivity.

To obtain some information in the central United States of the effect of forest watershed vegetation on the amount of water available for streamflow, soil mositure to a depth of 36 inches was studied for 22 months in southeastern Ohio on oak, pine, broomsedge, brush, and cleared plots. Moisture content near the end of the dormant season was used as a measure of field capacity. It varied from 11.49 inches of water on the pine plots to 13.12 inches of water on the broomsedge plots. Generally, soil moisture declined throughout the summer and increased during the winter, but occasionally summer rainstorms were large enough to rewet the soil to field capacity. Late‐summer soil moisture deficits were greatest under oak and least under cleared, whether calculated on the basis of measured field depths or on the basis of equal volumes of soil. Water used in a 6‐month growing season ranged from 21 inches under cleared to 25 inches under pine. Additional water was withdrawn during the dormant season. The 2‐year average amount of precipitation required to refill the soil was 6.5 inches greater under pine than under broomsedge—broomsedge being the minimum cover practical here. Good opportunities exist in Ohio to affect streamflow and flood control through the manipulation of the forest cover.

Information about free‐water surface evaporation on high mountain slopes is scarce because it is difficult to obtain a handy supply of water and to service research installations regularly in such remote locations. A recent study on areas at about 8200 feet elevation in the head of Parrish Canyon (Fig. 1) near Farmington, Utah, showed that small cans could be used to substitute for and to reduce the amount of ‘standard’ equipment needed. The small cans were much easier to service because only small amounts of replacement water were required. Plan of study. Evaporation was measured during the summers of 1957 and 1958 in Class A, 4‐foot‐diameter by 10‐inch‐deep, land surface pans and in 6.5‐inch‐diameter by 8.75‐inch‐deep cans [Weather Bureau, 1955]. The cans were shaded with horizontal sunshields of unpainted masonite because preliminary measurements indicated that water temperatures and evaporation were higher in the cans than in the pans.

A watershed's seasonal streamflow fluctuations are caused by meteorological conditions as they are modified by the watershed's inherent characteristics such as size, shape, aspect, geology, and plant cover. Records from Halfway Creek watershed, a perennial tributary to Farmington Creek located on the Wasatch Mountains in northern Utah, show that winter streamflow comprises only a small portion of the total annual yield. The winter contribution, which is low but constant, originates as drainage from deep aquifers. A much greater portion of the water yield comes in the spring as seepage flow derived from melting snow and spring rains, although the highest instantaneous spring peak so far recorded is only 24 csm (cubic feet per second per square mile). Initial recession of the flow of Halfway Creek from its spring peak is rapid, but in a short time its decrease becomes so gradual that in late summer the hydro graph becomes an almost flat line. The summer recession ends when climatic conditions in the autumn cause cessation of plant growth. Rainstorms often interrupt the normal summer recession. Most of these interruptions are brief, but the height of the peak varies widely. For instance, in the 24-year period when the vegetation cover was depleted, overland flow from short duration intense summer rainstorms caused mud-rock floods from Halfway Creek watershed that had instantaneous peaks 100 to 200times greater than the spring peak. The relations presented in this report were determined for a small area and are based on specific records. They apply in a general way to a much greater area in northern Utah and the Intermountain West of which they are representative.

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