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Agua Hedionda Lagoon is near Carlsbad, CA, and is near the middle of the Oceanside littoral sedimentation cell. Since its initial dredging in 1954, the lagoon has become a coastal sediment trap that must be dredged almost yearly. The purpose herein is to show the rate of sediment deposition in the lagoon from 1955 to 1961.

Analyses of water collected at 32 sites on headwater streams in Pennsylvania during low-flow conditions in 1979-1980 were compared to pre-1971 data to evaluate whether acid rain had changed the chemistry of the streams in the previous decade. Most pH alkalinity, and sulfate values of the samples collected in 1979-1980 fell within the ranges of values for samples collected before 1971. The limited data indicate, however, that pH may have increased and alkalinity and sulfate may have decreased with time. 7 references, 10 figures, 5 tables.

Tidal flow and suspended-sediment discharge were measured in or near the inlet to Bolinas Lagoon through seven ebbtides and six floodtides. The highest flows and suspended-sediment discharges occurred during the major daily ebbtide. Most transported sediment was sand and most sediment deposited in the lagoon was sand. Computations from a relation of suspended-sediment discharge and tidal range indicated that the annual suspended-sediment discharge of ebbtides exceeded that of floodtides by 9,000 tons. The highest concentration of suspended sediment occurred near the east shore of the inlet, which is at the end of a sand spit. The measured volume of water moved by a tide ranged from 180 to 2,740 acre-feet and the maximum flow measured was 7,900 cubic feet per second. The highest average velocity for a measurement was 4.9 feet per second. The maximum average velocity in the inlet occurred within an hour after midtide during a floodtide and usually at about one-third tide during an ebbtide. The relation of average tidal velocity (ut) to tidal range (R), was ut = 1.21R'50°; the average flow for a tide can be estimated by multiplying this calculated average velocity by the average cross section of the inlet.