Development issues regarding Bunot Lake: the Lesser Lake among the seven lakes of San Pablo City,Philippines

Bunot Lake exhibits the worst conditions among the seven crater lakes of San Pablo City in the Philippines. It is the most polluted lake, being oversaturated with fish pens/cages. It also hosts the largest concentration of illegal settlements. These attributes strongly suggest that Bunot Lake merits much greater attention in the agenda of its two administrative agencies, the Laguna Lake Development Authority (LLDA) and the City Government. The reality, however, is that Bunot Lake is lacking key development initiatives and programmes and seems to occupy a low priority to the LLDA and the City Government. This reality is particularly perplexing as the lake is located very near the urban centre, is closest to the premier lake (Sampaloc Lake), and is the site of the first commercial production of tilapia in floating cages in the city. Against this background, the present study identifies and analyses the immediate development issues for Bunot Lake. It contends that Bunot Lake should be given preference by the LLDA and the City Government, specifically by: (i) modifying their model‐template approach; and (ii) taking steps to tackle a basic need of Bunot Lake, namely the formulation of a zoning‐development plan. The present study also was designed to directly address the lacuna in Philippine lake studies, namely the paucity of research under the social science perspective (which is currently dominated by the natural science perspective) and on small lakes (which is currently concentrated on the largest lakes in the country).     

Development of a small lake: Ecotourism enterprise for Pandin Lake,San Pablo City,Philippines

This study examines the development of Pandin Lake, a small lake in the Philippines, particularly the unconventional evolution of the ecotourism enterprise for the lake and the accompanying issues. The study concludes that Pandin Lake ecotourism development is mainly an endogenous initiative and that the intervention of the relevant administrative agencies is critical in addressing the contemporary issues. This study discusses the following issues: (i) the reasons for studying small lakes in the Philippines; (ii) Pandin Lake and its administration; (iii) the ecotourism enterprise evolution and issues regarding the lake; and (iv) the conclusions. It also addresses the extant gap in Philippine lake literature: specifically the scarcity of scholarly works on development‐oriented studies, noting the field is dominated by limnology and aquaculture studies, and on small lakes, noting the field concentrates heavily on studies of big lakes.     

Drivers of water governance reforms in the Philippines

This paper analyses the enabling conditions for a water governance model responsive to future Philippine water requirements. Using the stage-based approach to institutional reforms, it assesses the outcomes of previous water governance reforms, such as conflicts in customary and formal rules; urban and rural; upstream and downstream; and the contestations in water supply privatization in Metro Manila. The analysis suggests that past water governance reforms were symbolic and procedural, and structural changes to support the legal frameworks were not achieved. Based on the case findings, the authors support the current reform agenda of implementing a decentralized framework of water governance at a watershed scale.     

Urban water demand,climatic variation,and irrigation-water insecurity: interactive stressors and lessons for water governance from the Angat River basin (Philippines)

Climatic variation and intersectoral water competition increasingly challenge the effective provision of irrigation services. This article explores their combined effects on irrigation allocation from the Angat Reservoir (Philippines), where domestic water use in Metro Manila has overtaken regional irrigation as the dominant right-holder. Rules protecting Metro Manila’s large right to water ‘interact’ with dry spells to affect irrigation security in wet and dry seasons. Historically, irrigators were uncompensated because re-allocation’s cause was contested as (1) an unforeseeable climatic event (releasing domestic utilities of liability), or (2) produced by urban demand (requiring compensation). Trade-off rules must be prepared to navigate combinatory effects.     

Enhancing institutional dynamics for multiple uses of water amidst climate‐related risks: The case of Lake Buhi,Philippines

This study examined the current governance system for Lake Buhi, Philippines. It describes stakeholder patterns of decision‐making, their roles in the decision‐making process based on their legal mandates, the manner of interactions, the sources of conflict and how these various issues are currently resolved. Stakeholders represent diverse interests, including irrigation, hydropower generation, fishery management and navigation. This study uses data generated from ten key informant interviews of the different stakeholders, information from five round table discussions, and secondary data and reports of various agencies. The results indicate that Lake Buhi and its watershed present classic man‐in‐nature governance challenges. The interplay of internal and external uncertainties regarding multiple uses results in a complex system that is difficult to effectively manage. Climate‐related hazards aggravate the pressures from activities within the lake watershed, complicating water allocation issues. The institutional arrangements that have emerged to address these challenges, however, appear to be fraught with overlaps, fragmentation and a lack of communication. It is thought these deficiencies could be addressed by establishing a lake basin council with representation from all the involved organizations, as well as any stakeholder groups not represented by organizations. The system of governance over the lake must address issues concerning water uses and access to the resource. The capacity of the organizations to participate in such an arrangement is weak, however, and capacity building is needed. The availability and sharing of data and information among stakeholders are also weak and must be strengthened if the work of the lake basin council is to be based on the best available information.     

Critical analysis of water governance challenges of Songkhla Lake Basin,Thailand

The present study examines water governance challenges in the Songkhla Lake Basin (SLB) with the aim of evaluating and analysing policies, legislations, regulations, institutions and actors responsible for the current state of the basin. The present study adopted three methodological approaches, including literature reviews, face‐to‐face expert interviews and field survey to investigate governance challenges confronting the SLB. It identified six major governance challenges that combined to produce current barriers to sustainable governance, resulting in depletion and deterioration of the SLB resource system. Moving forward will require pursuit of better resource management and governance systems, which will require strengthening of the Songkhla Lake Basin Committee to play a much needed coordinating and policy harmonization role to promote coherent actions among the formal and informal actors in the basin. Review of existing water resources and related governance instruments to make them appropriate, adequate and relevant for the sustainability of the SLB also is essential.     

Managing resources through stakeholder networks: collaborative water governance for Lake Naivasha basin,Kenya

Stakeholder analysis and social network analysis were used to analyze stakeholders’ social and structural characteristics based on their interests, influence and interactions in Lake Naivasha basin, Kenya. Even though the Kenyan government and its agencies seem to command higher influence and interest in water resource management, the presence of influential and central stakeholders from non-government sectors plays a key role in strengthening partnership in a governance environment with multiple sectors, complex issues and competing interests. Interactions in the basin are guided by stakeholders’ interest and sphere of influence, which have both promoted participation in implementing a collaborative water governance framework.     

Lake watershed management: Services,monitoring, funding and governance

This study discusses some insights for adaptive lake management from the perspective of ecosystem services (ES). Based on evidence from 46 advanced Payments for Watershed Services (PWS) projects implemented in 16 developing countries, and an interactive governance interpretation of this evidence, three layers of services for watershed management are distinguished, including (i) ES provided by ecosystems; (ii) land‐water conservation services (CS) provided by upstream citizens; and (iii) intermediary organizing services (OS) provided by watershed management organizations. The three‐layer service perspective indicates the need for management regime shifts regarding monitoring, funding and governance. A multilayer regime shift between monitoring, funding and governance for lake management also is discussed, using a Bolivian PWS scheme as an illustration. It indicates how lake management organizations can provide intermediary OS to coordinate exchanges between upstream payees and downstream payers. Upstream payees provide land‐water CS to obtain supply‐side payments. Land‐water CS improve water‐related ES to enhance downstream land‐water uses. Downstream payers provide demand‐side payments and benefit from better land‐water uses. This study was undertaken to broaden the vision of managing lakes and their watersheds and to guide policymakers, managers and other stakeholders in adopting adaptive management regimes for both locally and globally sustainable development.     

践行绿色发展理念持续推进太湖水环境治理工程建设

总结分析了2007年太湖蓝藻爆发发生水危机后,实施调水引流、蓝藻打捞、湖泛监控、河湖清淤等水利项目所取得的明显成效和经验;针对目前太湖水环境治理中面临的新问题和贯彻新时期治水方针的要求,提出了用绿色发展理念引领新一轮治太水利工程建设,从加强河湖连通、河湖疏浚整治和城市"活水"工程建设的实践,阐述了这一方法论的科学性、有效性;系统思考了完善太湖流域水环境治理体系的建议。     

Socio‐economic and institutional assessment of Malaysia's first biosphere reserve: Chini Lake

Despite being designated the first UNESCO Biosphere Reserve in Malaysia, the Chini Lake Basin experiences continuing management challenges attributable to existing sectoral management practices and differences in demands of multiple stakeholders. Accordingly, a socio‐economic survey and stakeholder consultative process were undertaken, involving relevant stakeholders in the lake basin. The consultative process involved: (a) identification and prioritization of relevant stakeholders; (b) assessment of their socio‐economic activities and perceptions; (c) organization of focus group discussions between basin stakeholders; and (d) development of management recommendations in collaboration with stakeholders. The results of this study indicated the local community's way of living has changed from traditional occupations to a wage economy. Overlapping functions and lack of communication were among the major identified challenges facing by Chini Lake. Multiple strategies were proposed to promote environmental protection and good governance of Chini Lake, including formation of special area plans and strengthening institutional arrangements to sustainably manage the Chini Lake catchment. An effective authority also is necessary to improve communication and coordination of programmes by the various basin agencies and communities.     

河西走廊流域治理的科学问题及其思考

针对河西走廊三流域治理,从水资源承载能力、社会经济发展模式、水资源利用秩序等方面,剖析各流域产生生态问题的科学必然性,以及流域治理手段的针对性。从黑河、石羊河流域治理的效果及流域演化基本规律出发,提出河西走廊三流域后治理时代可持续发展在气候变化、经济转型和粮食安全等方面的科学思考。     

Indications of the effects of climate change on the pelagic fishery of Lake Kariba,Zambia–Zimbabwe

The pelagic fishery of Lake Kariba comprises the introduced clupeid, Limnothrissa miodon, from Lake Tanganyika. The annual fishery catches grew logistically from 1974, when commercial fishing began. It peaked at 37 000 tonnes (estimated mean sustainable yield = 40 000 tonnes) around 1990 and declined steadily thereafter. A piecewise regression of Limnothrissa catches against time gives a breakpoint around 1987–1988. Regressions of Limnothrissa against air temperature and lake temperature gave breakpoints of 34.8 and 28.7 °C, respectively. Other studies indicate that Lake Kariba has warmed by close to 2 °C, with accompanying changes in thermal stratification. The lake phytoplankton is now dominated by Cyanophyceae, particularly Cylindrospermum raciborskii. The lake zooplankton population has greatly diminished. These data are similar to the results obtained for Lake Tanganyika (Nature 2003; 424 , 766–8). In the Lake Tanganyika study, the declining pelagic fishery has been attributed to reduced food availability resulting from a reduced phototrophic zone depth, as well as epilimnion nutrient recharge from reduced mixing. The warming observed in Lake Kariba and its environs is consistent with the IPCC Fourth Assessment Report (AR4). While the effects of global warming have been observed in large natural lakes, this is the first study in which global warming has affected the ecosystem of a large impoundment.     

Eutrophication of lakes in urbanized areas: The case of Yaounde Municipal Lake in Cameroon, Central Africa

A 1 year qualitative and quantitative evaluation of phytoplankton and chlorophyll‐a, as well as some physicochemical parameters, was recorded in a shallow tropical lake in Cameroon: the Yaounde Municipal Lake. Physicochemical measurements also were regularly made in its main tributary (Mingoa Stream). These analyses aimed to assess the lake's trophic status and to propose measures for controlling its degradation process. The Secchi disk transparency was low and rarely exceeded 100 cm. Conductivity was higher near the lake bottom. The oxygen deficiency, and sometimes anoxia, recorded from a 2.5 m depth leads to high quantities of ammonium‐nitrogen. The total phosphorus concentrations varied from 80–2290 µg P L^?1 and the total Kjeldhal nitrogen concentrations fluctuated between 3 and 15 mg  L^?1. Upstream to the lake, in the Mingoa Stream, total phosphorus concentrations ranged from 0.6–3.8 mg P L^?1 and total Kjeldhal nitrogen concentrations ranged from 10–22 mg  L^?1. There are up to 102 phytoplankton‐specific taxa, with Euglenophyta and Chlorophyta particularly more diversified. The phytoplankton biomass and chlorophyll‐a concentrations reached 225 µg mL^?1 and 566 mg m^?3, respectively. The analyses pointed out the allogenic nature of the functioning of this ecosystem as a result of bad waste management in the surrounding landscape. Urgent actions need to be undertaken in order to rehabilitate this lake, which rapidly shifted to a hypertrophic status.     

Towards adaptive governance for urban drought resilience: the case of Da Nang,Vietnam

Abstract

To address drought risks and risks of water shortages in cities it is essential to build resilience. Acknowledging that this is a process initiated by actors and institutions, this article presents a framework to analyze dynamics in the governance system for urban water services. The framework is applied to Da Nang, a drought-prone city in central Vietnam, to explore the elements and factors in the urban water sector that enhance or inhibit resilience to drought and find potential strategies to build resilience. The study finds that the framework has been helpful in identifying where changes and systematic interventions are needed to enhance resilience.     

Reconstruction of lake-level and climate changes in Lake Qarun,Egypt, during the last 7000 years

Sediment cores from Lake Qarun provide a record of mid-late Holocene climatic changes in Northern and Eastern Africa as well as environmental changes due to the activities of ancient Egyptians. We used sedimentological, mineralogical, and geochemical analyses of the cores to investigate long-term variations in lake level due to changing hydrologic inputs. An age model based on three paired ¹⁴C and paleomagnetic measurements suggests that the base of the sediment cores is as old as ∼ 5000 B.C.E. Geochemical analyses indicated that lake sediments were derived from Nile floods with an admixture of Saharan sand. Laminated endogenic carbonate-rich clayey silt lithofacies with benthic diatoms are indicative of relatively low lake levels, saline waters and dry conditions; massive lithofacies with planktonic diatom species are indicative of relatively high lake levels, fresh waters and humid conditions. Faintly laminated clayey silt lithofacies suggest intermediate conditions. Variations in lithology as well as diatom composition suggest that the lake level has varied from relatively high levels in its early history to lower levels in later years although there have been numerous cycles in water level over the past 7000 years. A combination of climate changes in the source area of the Nile River as a result of monsoon dynamics; climatic changes in the setting area of the Lake Qarun; and human activities through the dynasties in Egypt produced these variations in lake level.     

Progress Toward the Rehabilitation of Lake Trout (Salvelinus namaycush) in South Bay,Lake Huron

Our objective was to evaluate the status of lake trout Salvelinus namaycush rehabilitation in South Bay, Lake Huron. Standardized surveys were conducted to quantify natural recruitment, annual mortality, and the contribution of wild-versus hatchery-origin lake trout. Some indicators suggest a high level of natural recruitment. The spawning population was comprised of multiple ages, and the mean age of spawners (8.4 years for females, 7.9 years for males) was at least 1 year older than the age at 50% maturity (5.8 years). Estimated annual total mortality rates (0.20–0.25) and sea-lamprey induced mortality rates (0.02) were less than maximum allowable values. The proportion of wild-origin fish captured was high among spawners but varied among sampling programs (42% in fall trap nets, 70% in fall gill nets, and 88% in summer gill nets). A strong year class (1997) could be tracked from 2001 to 2005. Few fish were captured from early (< 1996) or later (1999–2002) year classes. Possible explanations for low natural recruitment during these later years include declining spawning habitat quality caused by low water levels and/or invasion of non-native mussels (Dreissena spp.) and/or direct or indirect effects of alewife (Alosa pseudoharengus).     

巢湖表层沉积物与环棱螺重金属分布特征及生态风险评价

以巢湖优势种淡水贝类——环棱螺与表层沉积物为研究对象,采用HNO_3-HF-HClO_4全消解法消解,然后使用电感耦合等离子体发射光谱仪(ICP-AES)对二者重金属(Cd,Cr,Cu和Pb)的总量分布进行研究,同时运用潜在生态风险指数法及单因子污染指数法与均方根综合指数评价二者重金属风险。结果表明:巢湖沉积物均已受到了一定程度的重金属Cd,Cr,Cu,Pb污染,其中以Cd的潜在生态风险最大,而环棱螺中则以Pb和Cr为高风险元素;重金属的分布特征和相关性分析显示,巢湖沉积物中的重金属来源具有相似性,而环棱螺对重金属的积累因多种环境因素的综合作用,使得环棱螺体内的重金属来源不同。因此,在未来的巢湖环境治理过程中,可着重考虑对重金属Cd,Cr,Pb的治理,同时应加大对贝类等生物监测措施的应用。     

Distribution and geochemical processes of boron in the multimedia of Lake Qinghai,China

Lake Qinghai on the Qinghai-Tibet plateau is the largest lake in China. This study investigated the concentration and geochemical processes of boron (B) in lake water, lake sediment and river samples collected from Lake Qinghai and the Buha River. In addition, lake sediment pore water samples were analyzed. The concentrations of B and major ions, including K⁺, Na⁺, Ca²⁺, Mg²⁺, Cl^? and SO₄^2?, were analyzed in all the water samples. The average concentration of B was 0.07?mg?L^?1, 6.37?mg?L^?1, 12.79) mg?L^?1 and 59.42?mg?kg^?1 for river water, lake water, pore water, and sediment, respectively. There were significant (p?<?0.05) and positive (r?=?0.70) relationships between the B concentrations in bottom water of the lake and in lake sediment, indicating that B diffusion from the sediment plays an important role in the concentration of B in bottom lake water. The differences in B concentrations and B/major ion molar ratios of the river water, lake water, and pore water indicated the following geochemical processes: 1) B is enriched in the lake water through evaporative concentration; 2) B is removed from the lake water through mineral precipitation as well as sorption onto colloids; 3) Solid-phase B in sediments was released through dissolution driven by organic matter mineralization. B/Cl and Na/Cl molar ratios alone are not enough to identify the sources of B in the water of inland closed-basin saline lakes because of these processes.     

An assessment of climate change and stratification in Lake Kariba (Zambia–Zimbabwe)

Lake Kariba is a monomictic reservoir, isothermal in winter (June–August), and stratified for the rest of the year. Its temperature has increased since the 1990s, with some researchers suggesting it now has a stronger and more stable thermocline as a result. It was also claimed that the depth of the epilimnion had decreased, and nutrient depletion has led to a decrease in the depth of the euphotic zone, algal biomass and primary productivity. A re‐analysis of the data suggests this view is incorrect. The epilimnion is more homogenous now than in the 1980s, with less vertical variation in temperature and dissolved oxygen in the upper 20 m of the lake. The depth of the euphotic zone has not changed since the 1960s, and the algal biomass and primary productivity have increased. The thermocline appears to have weakened with temperature and density gradients being much smaller than in the 1980s because of a more rapid rate of warming in deeper water. The reasons for this phenomenon are not clear, although evaporative cooling at the surface may contribute to it. There was a significant increase in Birgean heat budgets over time, although there was none for stability. This may be explained by the fact that the lake is monomictic, cooling to 22°C in winter, with a new cycle of stratification beginning each year, and it may be affected by variable factors such as evaporation, rainfall, river flow and internal wave movements.     

Detecting land use/land cover changes in the Lake Hayq (Ethiopia) drainage basin, 1957–2007

Land use/land cover changes in a lake drainage basin reflect changes in the magnitude of the water balance components and rate of sediment deposition in a lake as a reflection of the fundamental linkage between what happens in a lake considered against what is happening in the drainage basin of the lake. The objective of this study was to quantify the spatio‐temporal land cover/land use changes across the Lake Hayq 1 1 Lake Hayq is also locally called Lego.
closed drainage basin in north‐east Ethiopia over a 50‐years period, using multitemporal remote sensing and geospatial data. Two historical occasions of aerial photographs (1957 and 1986) and one satellite image (2007) were examined with image analysis tools: Leica Photogrammetric Suite (LPS 9.2) Project Manager, ArcGIS10.0, and ERDAS EMAGINE 9.2. Seven aerial coverage of land use/land cover categories were identified and mapped for the past three historical times. The results indicated that farmlands/settlements and shrublands/degraded lands increased by 43.1% and 136.9%, at an annual rate of 27.4 and 13.5 ha year^?1, respectively, between 1957 and 2007. In contrast, bushlands, grasslands, forestlands and lake surface area were diminished by 68.8%, 62.7%, 90.5% and 7.6%, at a rate of 24.0, 7.6, 6.1 and 3.7 ha year^?1, respectively, over the past five decades. The basin had undergone significant transformation in land use/land cover over the past half century, affecting the lake's biophysical stability by accelerating soil erosion in the basin, sediment accumulation, and a reduced quantity and quality of cumulative stream flow into the lake.