The creek basin is roughly , with of that above Freshwater Corners and above Freshwater town. The creek is at approximately sea level at its mouth and above at its headwaters. The highest that the creek basin as a whole rises above sea level is in the south east. At the mouth the rough annual rainfall is and at the headwaters it is . Most of the rainfall, between 35% and 40%, occurs in December and January. Snowfall is rare. The mean temperature of the creek water ranges from in summer to in winter. Prevailing winds are from the Pacific Ocean. In the tidal lower reach, the Slough, the creek is surrounded mainly by ranchland and residential properties. The creek gradient is low (), with
levees along most of the channel; the
riparian forest thin; and the water brackish. In the upper non-tidal reaches the riparian forest thickens with vegetation,
conifers, and
hardwood trees. The gradient is much steeper at . Most of the main river course is sparsely populated, with most of the watershed of the upper reaches being timberland that is owned and managed by the
Pacific Lumber Company. Most of the residential properties, including those of
Freshwater, are along the banks of the main creek. Logging activity has caused heavy erosion of the watershed, and Eureka Slough, via the Freshwater Slough, receives silt from the basin. == Tributaries and other locations ==