Ephemeral stream

Inputs from WWTP effluents can also affect the hydrologic and nutrient concentration regimes of recipient streams at different temporal scales. Daily variations of these parameters may be exacerbated in streams below the WWTP input by the diel patterns of the effluent discharge associated with plant operation [46]. In contrast, at the annual scale, seasonal variations of physical and chemical parameters upstream of the WWTP may be dampened by the constant input of additional water and nutrients from the WWTP. At its extreme, naturally intermittent or ephemeral streams may turn into permanent streams downstream of WWTPs [28, 30]. In these effluent-dominated streams, the relative contribution of WWTP inputs may vary widely on an annual basis, as shown by the 3-100% range measured in a Mediterranean stream [47]. Finally, WWTP inputs also cause shifts in the relative availability of N and P as well as in the relative importance of reduced and oxidized forms of N in the stream [30, 47]. The magnitude of these shifts depends on the level of wastewater treatment (i.e., primary, secondary, or tertiary treatment), the type of WWTP infrastructure (e.g., activated sludge reactor. 

Bone and tooth enamel from modem animals were collected in 1984 and 1993 from skeletons exposed on the surface in Sibiloi National Park, located on the east shore of Lake Turkana in northern Kenya. In addition to its interest as the site of numerous fossil hominid discoveries, the Turkana area provides an ideal controlled situation for the present study. The park is a circumscribed area surrounded by human pastoral groups and the nondomestic fauna remain to a great extent within its confines. Water sources are limited to the lake, ephemeral streams, a limited number of waterholes, and the plants eaten by the animals. The streams last on the order of days and in dry years do not flow at all. The non-domestic animals from which the bone and enamel were collected likely obtained most of their drinking water from the lake itself Domestic animals entered the park in 1984 during a severe drought. Their drinking water sources may have varied widely. 

The western portion of the Thomson project area is classified as desert, with rainfall <250 mm/yr. The eastern portion is classified as grassland, with rainfall 250-500 mm/yr (Caritat Lech 2007). Summers are hot and dry, winters cool. Highly variable rainfall results in ephemeral streams, particularly in the west, and many of the creeks and rivers flow only during flood events, which can be significant events. The low-gradient, sinuous and anastomosing streams, creeks and rivers broaden to include flood plains often several kilometres wide. It is during these events that fine silts and clays from the upstream catchment are deposited on the floodplains. 

Fluvial deposits (in isolation, and commonly as streams feeding the closed lake basins, Figure 10.3C) (f) alluvial fan-sandflat, (g) ephemeral stream floodplain and (h) perennial stream floodplain. 

Ephemeral streams Streams that flow intermittently. 

Robinson, A.R. (1957). Report on trapezoidal measuring flumes for determining discharges in steep ephemeral streams. Colorado State University Fort Collins CO. 

Neary, D.G., P.B. Bush, and M.A. Grant (1986). Water quality of ephemeral forest streams after site preparation with the herbicide hex-azinone. For. Ecol. Manage., 14 23 -0. 

Ephemeral a term used to describe a stream that forms only during or immediately after precipitation... 

Interflow waters. Synonymous with storm seepage waters runoff water which infiltrates the surface soil and moves laterally toward streams. Such water is ephemeral and shallow (above the main groundwater level). 

Storm sewers, springs, and surface creeks all drain into the Potomac River. As yet, significant sampling has not been performed to assess what if any contaminants are entering the river. The little sampling that has been done indicates a problem. Arsenic has been found in stream sediments and in the ephemeral pools along the river. Perchlorate was found in one storm sewer. Phenol hydrazine has been found in groundwater, which presumably enters the river. Thus, aquatic life is a potential receptor. 

Stream placers, because they occur in mountainous high-energy environments, are ephemeral deposits formed close to their source areas. Seldom are they preserved by lithification. Stream placers are known in North Carolina, South Carolina and Idaho in the U.S.A., British Columbia in Canada, India and Japan. 

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