China
Africa
Explore chapters and articles related to this topic
Subsurface Water in the Hydrologie Balance
Published in K. Ferguson Bruce, Stormwater Infiltration, 2017
Many surface streams like Peachtree Creek, where the water table is high enough to discharge to the surface drainage system, can continue to flow during long periods of dry weather. Water infiltrated into and stored in the subsurface emerges during later base-flow periods. Perennial stream flow and the volume of water in stream pools during low-flow periods determine a stream’s stability and productivity for aquatic ecosystems, human water supply, recreation and aesthetic interpretation. Stream water quality is a function of the stream’s dilution capacity (quantity of base flow) relative to the waste load from the drainage basin.
Water Ecology
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
In rain events, where the infiltration capacity of the soil is not exceeded, rain penetrates the soil and eventually reaches the groundwater—from which it discharges to the stream slowly and over a long period. This phenomenon helps to explain why stream flow through a dry weather region remains constant; the flow is continuously augmented by groundwater. This type of stream is known as a perennial stream, as opposed to an intermittent one because the flow continues during periods of no rainfall.
Water Ecology
Published in Frank R. Spellman, The Science of Water, 2020
In rain events where the infiltration capacity of the soil is not exceeded, rain penetrates the soil and eventually reaches the groundwater—from which it discharges to the stream slowly and over a long period. This phenomenon helps to explain why stream flow through a dry weather region remains constant; the flow is continuously augmented by groundwater. This type of stream is known as a perennial stream, as opposed to an intermittent one, because the flow continues during periods of no rainfall.
Streamside management zone effectiveness for water temperature control in Western Montana
Published in International Journal of Forest Engineering, 2019
Brian D. Sugden, Ron Steiner, Jay E. Jones
To qualify for the study, scheduled harvests had to meet several criteria. First, the harvest must border at least 300 m of fish-bearing perennial stream (along one or both sides of the stream). This distance was chosen to ensure that water temperatures have sufficient time to respond to the surrounding harvest conditions (Zwieniecki and Newton 1999). Second, harvest must occur in the fall, winter, or spring to ensure the minimum amount of time between pre- and post-harvest summer monitoring. Third, there could be no other harvest activities planned upstream or immediately downstream of the treatment area for the duration of the study. Each spring between 1999 and 2003, company foresters provided a list of all planned harvests in the coming year that met the above criteria. Each of these sites was field inspected, and all those verified to meet the criteria were included in the study.
Design of flexible barriers against sizeable landslides in Hong Kong
Published in HKIE Transactions, 2018
Eric H Y Sze, Raymond C H Koo, Jojo M Y Leung, Ken K S Ho
The study area (about 6 ha in area and 100 m in elevation difference) is located at Kwai Chung flanking Castle Peak Road (Figure 2). It comprises 11 hillside catchments, three of which contain incised drainage lines with perennial stream flow. According to the natural terrain hazard study (NTHS), six catchments were found to be posing undue landslide risk to the downslope facilities, including some cottages and the carriageways, pursuant to the react-to-known-hazard principle [13]. Potential landslide hazards in each vulnerable catchment were identified, as shown in Figure 2. The estimated design debris volumes (i.e. the design events) are also shown. The estimation was based largely on the largest recent landslides that took place in 1997 and 2008 within the study area. Together with the predicted entrainment volume for CDF, the largest design event was found to be 260 m3.
Tracking 1080 (sodium fluoroacetate) in surface and subsurface flows during a rainfall event: a hillslope-scale field study
Published in Australasian Journal of Water Resources, 2018
Under natural conditions, any 1080 in uneaten cereal baits can dissolve when baits are exposed to rain water (e.g. Bowen, Morgan, and Eason 1995). Dissolved 1080 can then either move downhill as overland flow, or move vertically into the soil with infiltrating rainfall. Few studies in the past have directly measured the fate and transport of 1080 released from baits. Parfitt et al. (1994) indicated that 1080 applied to high rainfall areas of NZ could potentially leach into soil. However, Bowman (1999) and Eason, Wright, and Fitzgerald (1992) did not find any evidence for 1080 contamination, based on field analysis of groundwater samples in areas where 1080 had previously been applied or stored. Srinivasan, Suren, et al. (2012) also argued that detection of 1080 in waterways early during rainfall events that immediately follow 1080 applications could only be explained by overland transport pathway, the quickest and shortest link between land and water. To better understand the fate of 1080 in baits that dissolves under rainfall and passes into receiving waters (including soil, ground and surface water), a field study was conducted in January 2012 at a hillslope adjacent to a perennial stream in the West Coast of South Island, New Zealand.