Selected reaches of Grant Line Arroyo and Tijeras Arroyo in Albuquerque, New Mexico, were studied to collect information about the amount and quality of infiltration through arroyo channels. Infiltration rate was calculated for selected reaches of Grant Line Arroyo and Tijeras Arroyo based on instantaneous streamflow-loss volumes, wetted channel area, and instantaneous evaporation rates measured during 1988-92. Infiltration rates at Grant Line Arroyo ranged from 0.0 to 0.6 foot per day, and at Tijeras Arroyo from 2.28 to 30 feet per day. The evaporation rate ranged from one-tenth of 1 percent to 2 percent of the infiltration rate. Infiltration rates differed with the location of the reach isolated for measurement and with the time of day of the infiltration-rate measurement. Differences in intrinsic permeability of the sediments may be the most important factor affecting spatial variations in infiltration. The most important factor affecting temporal variations in infiltration may be the temperature of the water and sediment where infiltration occurs. Annual evaporation rates were greatest over saturated stream sediments and ranged from 802 to 1,025 millimeters per year or from 31.57 to 40.35 inches per year. Annual evaporation rates were least over unsaturated, unvegetated soil and ranged from 174 to 291 millimeters per year or from 6.85 to 11.46 inches per year. Annual evapotranspiration rates over grasses or shrubs or both were about one-half the rates over saturated stream sediments. Rates were similar for Grant Line and Tijeras Arroyos. The land- surface vegetation, availability of water at the land surface, availability of energy to enable a change of state from water to vapor, existence of a vapor concentration gradient, and a turbulent atmosphere to carry the vapor away may be the factors that determine the amount of evaporation and evapotranspiration. Water in Grant Line Arroyo and Tijeras Arroyo met U. S. Environmental Protection Agency drinking-water regulations for nitrate, volatile organic compounds, dissolved lead, and dissolved and total arsenic, barium, cadmium, chromium, copper, iron, silver, zinc, selenium, chloride, and sulfate concentrations. Total lead concentration in one sample from Tramway Floodway Channel, a tributary to Tijeras Arroyo, was 55 micrograms per liter, exceeding the Environmental Protection Agency drinking-water regulation of 50 micrograms per liter. Dissolved-solids concentrations calculated from the sum of cations and anions usually exceeded the Environmental Protection Agency drinking-water dissolved-solids regulation of 500 milligrams per liter at Tijeras Arroyo above Four Hills Bridge.