Environmental Management
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Item Climate Change Induced Variations in Rainfall Patterns and Potential Adaptation Options of DL1b Agro-Ecological Zone of Sri Lanka: A Case Study(Institute of Biology Sri Lanka, Colombo., 2020) Udayanga, L.N.W.B.A.; Najim, M.M.M.An analysis of the shifts and trends of climate patterns with respect to wet and dry events and rainfall seasonality is vital for the effective planning and management of water resources in tropical countries such as Sri Lanka, which have agriculture-based economies. Hence, temporal and spatial variations of climate extremes and rainfall seasonality in Sri Lanka, were evaluated in the DL1b Agro-Ecological Zone through the Standardized Precipitation Index (SPI) and Seasonality Index (SI) utilizing 58 years of daily rainfall data of five selected localities. The Chi-square test of independence was used to statistically compare the percentage occurrence of each event recorded during 1961-1988 and 1989-2018. The dryness of all study areas denoted increments in terms of both severity and frequency of occurrence in accordance with SPI. However, among the studied localities of the DL1b agro-ecological zone, only the increment of dryness in Vavuniya remained statistically significant (Χ2 (df = 4) <9.78; P=0.04) at 95% level of confidence. Rainfall seasonality of the localities was characterized with a markedly seasonal climatic condition with a long, dry season (0.95 – 0.97) with no significant variations and shifts. Cultivation of low water demanding crops, adjustment of cropping seasons, use of more efficient water smart irrigation methods, implementation of agro-forestry systems and employment of smart and integrated watershed management practices could be recommended as potential adaptation measures to compensate the impacts of climatic change.Item A Mathematical Model for Control of Drainage in an Irrigation System(Emerging Challenges to Food Production and Security in Asia, Middle East, and Africa. Springer, Cham, 2021) Hajiyev, A.; Rustamov, Y.; Najim, M.M.M.Mathematical models describing the estimation of optimal amounts of water depend on various parameters such as the quality of soil that depends on many random factors. Investigation methods and approaches of the random processes of those parameters play an important role. In irrigation systems, drainage systems are widely used to achieve multiple objectives and it is necessary to pay attention to the choice of mathematical models that are adequately describing the processes of drainage and control of groundwater levels. An algorithm for the regulation and prevention of salinization of arable land and swampy areas in addition to an estimation of the amount of drainage water, have been proposed. Behaviour of the groundwater (temporal variation) is analysed applying the proposed model. Under the given conditions, it was derived that for an isotropic and homogeneous case, the level of the priming relative to axis x is approximately stable. A change in other parameters leads to the reduction of the effectiveness of drainage system and, consequently, to decreasing the level of water. Hence, using some engineering processes, it is necessary to increase the velocity of water through the drainage system.Item Assessment of current water pollution status and accumulation of trace metals in Mugil cephalus from Negombo estuary(Journal of Threatened Taxa, 2021) Najim, M.M.M.; Kithsiri, H.M.P.Industrial and domestic solid waste dumping are the major pollution sources polluting the Negombo estuary. Polluted water and sediments in the estuary may cause heavy metals accu mulation in fish. Therefore, this study was aimed to assess physico - chemical parameters in water, heavy metals (Zn, Pb, Hg, Cd, Cu and Cr) in water and fish tissues, to compare the levels of metals in fish tissues with the available maximum recommended standards. The study was carried out from January to December 2016 and monthly sampling was done from the selected sampling sites. Physico - chemical parameters and metal levels were detected through standard methods. Water quality results revealed that temperature, salinity, pH, EC, TSS, BOD and nutrient levels were below the maximum permissible limits and COD levels were higher than the discharge of industrial wastewater quality standards of the CEA, Sri Lanka. According to the results, metal levels in water of the estuary were below the tolerance limits for the wastewater standards of the CEA except for Hg. In the Northern region of the estuary, higher Pb, Cu and Cr levels were reported from the fish species collected. As the “X-Press Pearl” shipwreck has posed a serious threat to the Negombo estuary, this study can be considered as a baseline for the future studies on water and sediment pollution and bioaccumulation of heavy metals in edible fish species from the estuary.Item Treatment and Disposal of Poultry Processing Wastewater in Sri Lanka(Sri Lanka Journal of Technology, 2021) Wijesekra, W.R.L.; Lokupitiya, E.; Najim, M.M.M.—Discharge of untreated poultry processing wastewater (PPWW) causes various environmental pollution issues in the re ceiving environment of water, land, and air. Treatment and disposal of PPWW in compliance with disposal norms is one of the main concerns of poultry meat production industries in Sri Lanka. In many countries, PPWW is treated using either Anaerobic Biological Treatments (ANERBTs) incorporated with energy recovery or Aero bic Biological Treatments (AERBTs) and discharged into municipal sewage systems for further treatment. The primary aim of this paper is to estimate organic strength characteristics (OSCs) of untreated PPWW in terms of COD and to provide an overview of the existing treatment technologies, its compatibility, and treated wastewater (TWW) disposal practices since no sound written documents or sci entific studies done in Sri Lanka are reported. In this study, COD of untreated PPWW was used to determine its OSCs and compatibility of treatment techniques of existing treatment facilities. The field sample analysis reported COD of above 1,605mg/l assuring high OSCs of PPWW and evaluation of existing treatment methodologies surprisingly highlighted a very few applications of ANRBTs in the local PPIs, though ample research evidence is available on the application of ANRBTs for the treatment of wastewaters with high OSCsItem Distribution notes on the Endangered freshwater crab Ceylonthelphusa armata Ng (1995) (Crustacea: Brachyura: Gecarcinucidae) in Sri Lanka(Journal of Threatened Taxa, 2021) Udagedera, U.S.C.; Gabadage, D.E.; Najim, M.M.M.There are 52 species of freshwater crabs in Sri Lanka and 51 of them are endemic. There are several species that are known only from a single locality. Ceylonthelphusa armata is such a species, and we have initiated a study to record the distribution of this species as its typical locality is heavily polluted at Kadugannawa. At present C. armata is known from six localities, and this information will be useful to facilitate the conservation of the species by assessing the Red List.Item Impacts of streamflow alteration on benthic macroinvertebrates by mini‐hydro diversion in Sri Lanka(mini‐hydro diversion in Sri Lanka, 2021) Munasinghe, D.S.N.; Najim, M.M.M.; Quadroni, S.; Musthafa, M.M.Our study focused on quantifying the alterations of streamfow at a weir site due to the construction of a mini-hydropower plant in the Gurugoda Oya (Sri Lanka), and evaluating the spatial responses of benthic macroinvertebrates to altered fow regime. The HEC–HMS 3.5 model was applied to the Gurugoda Oya sub-catchment to generate streamfows for the time period 1991–2013. Pre weir fows were compared to post-weir fows with 32 Indicators of Hydrologic Alteration using the range of variability approach (RVA). Concurrently, six study sites were established upstream and downstream of the weir, and benthic macroinvertebrates were sampled monthly from May to November 2013 (during the wet season). The key water physico-chemical parameters were also determined. RVA analysis showed that environmental fow was not maintained below the weir. The mean rate of non-attainment was ~ 45% suggesting a moderate level of hydrologic alteration. Benthic macroinvertebrate communities signifcantly difered between the study sites located above and below the weir, with a richness reduction due to water diversion. The spatial distribution of zoobenthic fauna was governed by water depth, dissolved oxygen content and volume fow rate. Our work provides frst evidence on the efects of small hydropower on river ecosystem in a largely understudied region. Studies like this are important to setting-up adequate e-fows.