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Water Treatment
Published in Frank R. Spellman, The Drinking Water Handbook, 2017
When the mixing zone conditions have been met, the outfall structure can be properly designed and installed. Actually, the purpose of the outfall structure is to ensure that mixing conditions can be met and that discharge of the effluent, in general, will not produce any damaging effect on the receiving water, its lifeforms, wildlife, and the surrounding area. In a highly turbulent and moving receiving water with large volume relative to the effluent discharge, simple discharge from the end of a pipe may be sufficient to ensure rapid dilution and mixing of the effluent. For most situations, however, the mixing can be improved substantially through the use of a carefully designed outfall structure. Such a design may be necessary to meet regulatory constraints. The most typical outfall structure for this purpose consists of a pipe of limited length mounted perpendicular to the end of the delivery pipe. This pipe, called a diffuser, has one or more discharge ports along its length.
Simulation of Regional Water Systems
Published in Arnold H. Lobbrecht, Dynamic Water-System Control, 2020
The storage capacity of a combined sewer system is limited, e.g. to 7 or 9 mm. Outfalls are constructed at specific locations to prevent streets and adjacent areas from being flooded by polluted water when the storage capacity is reached in part of or in the entire sewer system. This overflow is called combined sewer overflow (CSO). Some outfalls can be controlled, but most of them are fixed. In exceptional situations, the discharge capacity of the sewer system to the outfalls may become too low. Sewers flooding streets may be the undesirable result of such undercapacities.
Feasibility of Advanced Water Purification Processes
Published in Frank R. Spellman, Land Subsidence Mitigation, 2017
When the mixing zone conditions have been met, the outfall structure can be properly designed and installed. Actually, the purpose of the outfall structure is to ensure that mixing conditions can be met and that discharge of the effluent, in gen- eral, will not produce any damaging effect on the receiving water, its lifeforms, wildlife, and the surrounding area.
A topological characterisation of looped drainage networks
Published in Structure and Infrastructure Engineering, 2022
Didrik Meijer, Hans Korving, François Clemens-Meyer
The NLP was determined for the seven UDNs. Table 5 and Figure 8 present the results. In Figure 8, each dot represents a bottleneck. The size and greyscale colouring visualise the number of nodes of the UDN that discharge via the bottleneck see % affected manholes in Figure 8). The larger and darker the dot, the higher is the percentage of affected manholes. On the x-axis is the applied threshold for the bottleneck. The bottlenecks per combined sewer outfall or storm sewer outflow of the UDN have been plotted side by side for each threshold. The position of the bottleneck is on the y-axis. The position has been normalised per outfall based on the maximum path length to the outfall. The numbers on top of each plot indicate the number of bottlenecks per threshold for the outfall with the highest number of bottlenecks.
Nutrient dynamics in a eutrophic blackwater urban lake
Published in Lake and Reservoir Management, 2022
Nicholas D. Iraola, Michael A. Mallin, Lawrence B. Cahoon, Douglas W. Gamble, Peter B. Zamora
Perennial surface water input into the lake is from 5 streams, including an unnamed branch designated GL-2340, Silver Stream Branch (GL-SSB), Clay Bottom Branch (GL-CBB), Jumping Run Branch (GL-JRB), and Squash Branch (GL-SQB, also known as Lake Branch, GL-LB; Figure 1). Each stream’s subwatershed (Table 1; Cohick S, City of Wilmington Stormwater GIS Manager, 2018, unpubl. data) is differentiated by its catchment characteristics, such as drainage size, impervious area, and impervious cover percentage (Mallin et al. 2016). GL-JRB is the largest subwatershed, at 322 ha. It has the second largest impervious area (83 ha), but the smallest percent impervious area (26%), in part because of the large golf course (72 ha) located within the subbasin. GL-2340 has the largest impervious area (126 ha) and the highest percent impervious area (74%). The lower watersheds of both Silver Stream and GL-2340 contain large constructed wet detention ponds and significant natural wetlands located upstream of the inputs into the lake. We note that unaccounted local drainage enters the lake from direct shoreline stormwater runoff and a few small ephemeral streams and drainage ditches. Water exits the lake via the lake outfall at Greenfield Creek, which drains into the Cape Fear River.
Impact assessment of urbanization on flood risk and integrated flood management approach: a case study of Surat city and its surrounding region
Published in ISH Journal of Hydraulic Engineering, 2021
Rupal K. Waghwala, P.G. Agnihotri
Tapi River begins its journey from the Multai Hills in the Gavilgad hill ranges of Satpura Mountain (Betul district) in Madhya Pradesh, at an elevation of 752 m above sea level. It travels for a distance of about 725 km, out of which its last stretch of 214 km is in the Gujarat state. The Tapi River has a total catchment of 65,145 km2, its drainage area lies in three states: Madhya Pradesh (9,804 km2), Maharashtra (51,504 km2) and Gujarat (3,837 km2). The basin has an elongated shape, divided into three sub-basins: Upper Tapi Basin, Middle Tapi Basin and Lower Tapi Basin with 29,430 km2, 28,970 km2, and 6,745 km2 respectively. Surat city and its surrounding regions are a part of the Lower Tapi Basin situated in the western part of India. The river outfall into the Arabian Sea is 20 km downstream of the Surat city. The Lower Tapi Basin from Ukai to the Arabian Sea collects 1376 mm average annual rainfall, consequently making it the biggest reason for floods to occur.