Drainage in urban water environment

Good drainage improves the waterways from the place of origin is released. However, improper waste management system in drainage could lead pollution in streams and rivers. In the case study in Batu Pahat town, there are several issues arise on drainage system. One of the main problems that caused the drainage get clogged is food waste from restaurants especially in closed drainage. There are several effects that are encountered if the waste management in the drainage system is poor. The effects could happen on human, flora and fauna, and environment. The aim of this chapter will identify the method of practices that has been used for cleaning the drainage. Responsibilities of local authorities in cleaning the drains at Batu Pahat will be explained. The best management practise to overcome the drainage pollution issues will be highlighted

Seasonal surface drainage of sloping farmland : a review of its hydrogeomorphic impacts

The combination of runoff-generating areas (saturated soils) and overland flow concentration in features such as drainage ditches makes sloping farmland vulnerable to soil erosion. The establishment of drainage ditches aims at draining the excess of water from the farmland, particularly in areas where soils are saturated in the rainy season. The hydrogeomorphic impacts on the farmland itself and on downstream areas need however also to be studied. Off site, downstream problems comprise higher peak discharges, leading to gully initiation, an increase in sediment load, and flooding problems. On-site problems such as the development of the drainage ditches into (ephemeral) gullies are less documented, although they may be important, as illustrated in the Lake Tana Basin (Ethiopia). The similarities and interactions between ephemeral gully channels and drainage ditches have to be considered to better understand all effects of drainage. Drainage ditches are a potential source of conflict between farmers with different interests and power, as well as between upstream and downstream users. A case study on drainage ditches on sloping farmlands in the Lake Tana Basin showed that nine out of ten catchments had drainage densities by ditches ranging from 53 to 510 m ha−1. Drainage ditches were constructed with an average top width of 27 (±9) cm. A significant correlation was found between stone bund density (physical conservation structures) and ditch drainage density (R = −0·72), in line with the Ethiopian government's ban on drainage ditches in farmlands where stone bunds have been constructed

Design and construction aspects of a geocomposite drainage system in a dam

The drainage system of a dam depends mainly of the available granular material founded near the dam site and it’s quantities. In some cases, the use of natural granular materials can reach an impracticable cost considering the transportation and the required quality of the material. Geosynthetic materials and, in particular, drainage geocomposites offers constructive alternatives to traditional solutions on internal drainage systems. This paper discusses the design and construction of a geosynthetics system, and presents a case in which a traditional granular material drainage system was successfully replaced by a geocomposite drainage syste

Drainage and retention of water in small drainage cavities : experimental assessment

Water that enters the drainage cavity of a rain screen wall assembly through deficiencies in the cladding will either be drained or retained by absorption or adhesion on the drainage surfaces. The objective of this study is to gain insight into the different factors that affect the quantity of water drained or retained in a drainage cavity. Drainage tests have been conducted for water flowing between two vertical polycarbonate plates with different gap widths to determine the effect on the drainage rate. Tests showed that even small cavities with a width of 1 mm can already drain more water than the amount that would enter the cavity during a rain event. Experiments were performed to determine the contact angle of water on a range of different sheathing materials such as asphalt saturated building paper, spun-bonded polyethylene wrap and cross-woven polyolefin wrap by the use of an optical goniometer. Drainage tests have been conducted for different combinations of these materials to quantify the effect of surface energy on the drainage rate. A larger contact angle results in a smaller quantity of water retained during the drainage test. These tests result in a retained portion of water and a drainage rate for different combinations of materials. The retained portion of water may be considered as a moisture load applied to the outer-most layer of the wall assembly’s back-up wall in hygrothermal simulations

Thoracic duct drainage in organ transplantation: Will it permit better immunosuppression?

It is possible that thoracic-duct drainage, a major but neglected immunosuppressive adjunct, can have an important impact on organ transplantation. If thoracic-duct drainage is started at the time of transplantation, the practicality of its use in cadaveric cases is greatly enhanced. With kidney transplantation, the penalty of not having pretreatment for the first organ is compensanted by the automatic presence of pretreatment if rejection is not controlled and retransplantation becomes necessary. The advantage of adding thoracic-duct drainage to conventional immunosuppression may greatly enhance the expectations for the transplantation of extrarenal organs, such as the liver, pancreas, heart, and lung. There is evidence that pretreatment with thoracic-duct drainage of patients with cytotoxic antibodies may permit successful renal transplantation under these otherwise essentially hopeless conditions. Exploration of the neglected but potentially valuable tool of thoracic-duct drainage seems to the authors to be highly justified in other centers

A cost comparison of traditional drainage and SUDS in Scotland

The Dunfermline Eastern Expansion (DEX) is a 350 ha mixed development which commenced in 1996. Downstream water quality and flooding issues necessitated a holistic approach to drainage planning and the site has become a European showcase for the application of Sustainable Urban Drainage Systems (SUDS). However, there is minimal data available regarding the real costs of operating and maintaining SUDS to ensure they continue to perform as per their design function. This remains one of the primary barriers to the uptake and adoption of SUDS. This paper reports on what is understood to be the only study in the UK where actual costs of constructing and maintaining SUDS have been compared to an equivalent traditional drainage solution. To compare SUDS costs with traditional drainage, capital and maintenance costs of underground storage chambers of analogous storage volumes were estimated. A whole life costing methodology was then applied to data gathered. The main objective was to produce a reliable and robust cost comparison between SUDS and traditional drainage. The cost analysis is supportive of SUDS and indicates that well designed and maintained SUDS are more cost effective to construct, and cost less to maintain than traditional drainage solutions which are unable to meet the environmental requirements of current legislation

Modelling foam drainage

Foaming occurs in many distillation and absorption processes. In this paper, two basic building blocks that are needed to model foam drainage and hence foam stability are discussed. The first concerns the flow of liquid from the lamellae to the Plateau borders and the second describes the drainage flows that occur within the borders. The mathematical modelling involves a balance between gravity, diffusion, viscous forces, and varying surface tension effects with or without the presence of monolayers of surfactant. In some cases, mass transfer through the gas-liquid interface also causes foam stabilisation, and must be included. Our model allows us to clarify which mechanisms are most likely to dominate in both the lamellae and Plateau borders and hence to determine their evolution. The model provides a theoretical framework for the prediction of foam drainage and collapse rates. The analysis shows that significant foam stability can arise from small surface tension variations