Jagath Manatunge

Livelihood Rebuilding of Dam-Affected Communities: Case Studies from Sri Lanka and Indonesia

This paper discuss two cases of resettlement related to dam development: the Saguling project in West Java and the Kotmale project in Sri Lanka. Resettlers of these two projects were offered new livelihoods created by the project. Their successes and failures in restoring income subsequent to relocation are discussed. In both the projects, alternative compensation schemes had to be formulated because it was not possible to provide resettlers with the same amount of farmland in the vicinity. The strategic use of new opportunities, by way of providing new prospects in aquaculture development, was promoted as compensation for resettlers of Saguling and, as a result, they were able to enjoy superior economic and social benefits. Two options, based on income restoration through land-based alternatives, were offered for Kotmale resettlers: move away to new settlements or resettle in riparian areas after receiving tea plots. Two decades after relocation, their socioeconomic conditions are better than those who were not affected by the project. However, many questions remain which raise doubts whether resettlers were able to reap the intended benefits; these are discussed in this paper. Some of them include issues of social marginalization and inequality, the negative consequences of lack of access to credit, and over-exploitation of resources that eroded the earnings potential. The following lessons were learnt from the two case studies: livelihood rebuilding efforts should be complemented by introducing opportunities of securing financial assistance; attitude towards risk is crucial in the success of livelihood rebuilding; resettlement options should address the dynamism of local socio-economic conditions and be designed with local collaboration; sustainability of production capacity and economic viability in the long term should be emphasized; and while outsider influence cannot be controlled, the capacity of the local community can be strengthened.

Long-term perceptions of project-affected persons: a case study of the Kotmale Dam in Sri Lanka

Many of the negative consequences of dam-related involuntary displacement of affected communities can be overcome by careful planning and by providing resettlers with adequate compensation. In this paper the resettlement scheme of the Kotmale Dam in Sri Lanka is revisited, focusing on resettlers positive perceptions. Displaced communities expressed satisfaction when income levels and stability were higher in addition to their having access to land ownership titles, good irrigation infrastructure, water, and more opportunities for their children. However, harsh climate conditions, increased incidence of diseases and human–wildlife conflicts caused much discomfort among resettlers. Diversification away from paddy farming to other agricultural activities and providing legal land titles would have allowed them to gain more from resettlement compensation.

Restoration of Koggala lagoon: modelling approach in evaluating lagoon water budget and flow characteristics.

Groyne system modification is described related to restoration efforts to Koggala lagoon, Sri Lanka.The large-scale unplanned sand removal at the lagoon mouth shifted the formation of sand bar towards the lagoon and made adverse effects on its ecosystem. After the removal of the natural sand bar, groyne system was constructed to avoid sand deposition in the lagoon and to protect the highway bridge (across the lagoon outlet channel) from the wave attack. The existing groyne system resulted the lagoon mouth being permanently open to sea which in turn led to many environmental problems. Groyne system modification is proposed in this study to reduce the sea water intrusion. Water budget and two-dimensional depth averaged hydrodynamic model were developed for understanding the hydrologic and flow characteristics of the lagoon. Numerical experiments was performed at lagoon mouth area for two cases: (1) existing condition and (2) proposed rubble mound groyne system condition. Comparison of results was obtained for both cases to describe flow pattern at lagoon mouth. Results further showed, the width should be reduced to a maximum of 40 m. Proposed mouth width (40 m) pushed the salting factor towards 0.5 from 0.68. Salting factor reduction with the groyne modification may result a predominant influence of fresh water which may in turn lead lagoon to a fresh water ecosystem.

Rapid degradation of FOG discharged from food industry wastewater by lipolytic fungi as a bioaugmentation application

ABSTRACT Fats, oils and grease (FOG) congregate in grease traps and are a slowly biodegradable particulate organic matter, which may require enzymatic or hydrolytic conversion to form readily biodegradable soluble organic matter. The existing treatment methods employ water-based hydrolysis of FOG to form long-chain fatty acids (LCFAs). The LCFAs discharged into wastewater treatment system create functional difficulties, especially the inhibitory effect caused by accumulation of LCFAs. This study aims to find an effective treatment method for this persistent problem encountered in conventional wastewater treatment system. Solid-state degradation by lipolytic fungi was performed in a tray-type reactor as a novel approach of bioaugmentation. Grease trap waste samples were dried to have moisture content of 25–35% and mixed with coir fiber (1% w/v) for proper aeration. Each 10u2005mg/g dry weight of substrate was inoculated with 1u2005mL of spore suspension (1u2009×u200910⁷ spores/mL) of lipolytic fungi. Thereafter, moisture content in the reactor was increased to 65%, and incubated at 30°C. Within 72u2005h of post incubation, degradation efficiency of about 50% was recorded by fungal isolates. The feasibility of using developed protocol for FOG degradation was tested with a laboratory-scale prototype reactor.

Mud Crab (Scylla serrata) population changes in Koggala Lagoon, Sri Lanka since construction of the groyne system

This study was conducted to determine the present status of the Mud Crab (Scylla serrata Forskal) population in Koggala Lagoon, including details on size at maturity, sex ratio and carapace width - body weight relationship. This Crab is the most common edible Crab species found in the lagoon, comprising 93.10% of total catch from crab pots and 89.86% of total catch from crab nets. Sex ratios (male:female) were 1:0.86 and 1:0.82 in crab pots and nets, respectively. Female crabs of various sizes were randomly sampled to determine size at maturity. The results indicate that size at maturity of females was 12.17 cm carapace width. Size at maturity of males could not be determined using external characteristics. Population parameters were estimated from length-frequency data collected in 2009 and 2011. Asymptotic carapace length (L∞) and growth constant (K) were estimated to be 20.12 cm, 0.91 yr−1 in 2009 and 19.27 cm, 3.2 yr−1 in 2011, respectively. Exploitation rates were 0.32 in 2009 and 0.44 in 2011. There was a significant difference in Crab size between harvests by the crab nets versus traditional crab pots. Results indicate that S. serrata population is declining due to over-fishing as of increased fishing gear efficiency from traditional crab pots to modern crab nets. Commercial catches of crab net and crab pots comprised 85.7% and 72.0% of immature females, respectively, based on the size at first maturity revealed by this study. In order to maintain natural health of the Mud Crab population, immediate management action is needed to regulate fishing in Koggala Lagoon.

Effect of inlet morphometry changes on natural sensitivity and flushing time of the Koggala lagoon, Sri Lanka

The changes of natural sensitivity in terms of lagoon morphometry, particularly the inlet morphometry and flushing properties of the Koggala lagoon, Sri Lanka, are presented in this paper. The morphometric assessment is based on analysis and consideration of morphometric characteristics for three scenarios of the lagoon, namely: (1) before the construction of the old groyne system or time period before 1996 (Koggala Scenario 1—KS1); (2) existing situation or time period after 2007 (Koggala Scenario 2—KS2); and (3) future scenario with respect to proposed groyne interventions for the mouth width of 20xa0m, as proposed by Gunaratne et al. (J Environ Sci 22(6):813–819, 2010) (Koggala Scenario 3—KS3). The morphometric assessment provides a simple means of defining natural sensitivity or vulnerability of individual scenarios of Koggala lagoon to external loads and anthropogenic activities. We found that KS1 and KS3 scenarios are relatively more sensitive than KS2, whereas KS1 has the highest natural sensitivity, and KS2 has the lowest natural sensitivity or the most robust conditions. In quantifying the tidal flushing of Koggala lagoon, the concept of flushing half-life (T50% h) was adapted as the optimum measure of flushing time. Flushing half-life was calculated for KS2 and KS3 scenarios. The flushing half-life ranges from 9 to 37xa0h (1.5xa0days) for KS2 and from 12 to 72xa0h (3xa0days) for KS3. Flushing half-life suggests that the exchange rate between the lagoon and the ocean is controlled by the balance between fresh water inflow and the seawater inflow. Applications of the morphometric classification and flushing half-life presented in this article can be used to help guide management and policy-making decisions for the coastal environment of Koggala lagoon and other coastal water bodies of Sri Lanka.

Dealing with algal toxins and dissolved organics in drinking water

AbstractSeveral types of cyanotoxins found in surface water bodies are recognized as having human health effects, whereas taste and odor affect the palatability of water and give rise to public complaints. Conventional water treatment unit operations may be effective in removing the cyanobacteria cells, but cyanotoxins and dissolved organics are not targeted for removal by them. Special treatment units need to be introduced to deal with these substances and attention paid to the process design as many operational issues may be encountered. We used a water supply project in the Eastern Province of Sri Lanka as a case study to investigate the performance of unit operations in water treatment plants for which the source is shallow surface water sources with high inflows of nutrients. The present case study was designed to evaluate the efficacy of prechlorination, activated carbon adsorption, dissolved air flotation (DAF), filtration and disinfection in removal of cyanotoxins, and taste and odor causing disso...

Glyphosate and AMPA of agricultural soil, surface water, groundwater and sediments in areas prevalent with chronic kidney disease of unknown etiology, Sri Lanka

Abstract Glyphosate, which is commercially available as Roundup®, was the widely used herbicide in Sri Lanka until 2015 and is suspected to be one of the causal factors for Chronic Kidney Disease of unknown etiology (CKDu). This research, therefore, aims at studying the presence of glyphosate and Aminomethylphosphonic acid (AMPA) in different environmental matrices in CKDu prevalent areas. Topsoil samples from agricultural fields, water samples from nearby shallow wells and lakes, and sediment samples from lakes were collected and analyzed for glyphosate and AMPA using the LC/MS. Glyphosate (270–690 µg/kg) and AMPA (2–8 µg/kg) were detected in all soil samples. Amorphous iron oxides and organic matter content of topsoil showed a strong and a moderate positive linear relationship with glyphosate. The glyphosate and inorganic phosphate levels in topsoil had a strong negative significant linear relationship. Presence of high valence cations such as Fe3+ and Al3+ in topsoil resulted in the formation of glyphosate-metal complexes, thus strong retention of glyphosate in soil. Lower levels of AMPA than the corresponding glyphosate levels in topsoil could be attributed to factors such as the strong adsorption capacity of glyphosate to soil and higher LOQ in the quantification of AMPA. The glyphosate levels of lakes were between 28 to 45 µg/L; no AMPA was detected. While trace levels of glyphosate (1–4 µg/L) were detected in all groundwater samples, AMPA (2–11µg/L) was detected only in four out of nine samples. Glyphosate was detected in all sediment samples (85–1000 µg/kg), and a strong linear relationship with the organic matter content was observed. AMPA was detected (1–15 µg/kg) in seven out of nine sediment samples. It could be inferred that the impact on CKDu by the levels of glyphosate and AMPA detected in the study area is marginal when compared with the MCL of the USEPA (700 µg/L).