Application of algal bioassays in the determination of eutrophic power of waste water (”Conclusions” only) [Translation from: 1g.Sanita pubbl. 31 257-267, 1975]

The best evidence for establishing the level of eutrophy of a water-body is its algal production which makes it possible to identify the type and the intensity of the eutrophication according to the kind and number of algal species present: when the number of algae exceeds half a million per litre then one speaks o an ”algal bloom”. The scope of the present research aims to verify if the alga Selenastrum capricornutum can be used as a test alga under our culture conditions and to determine the eutrophic level of the secondary effluent of a modern plant for the treatment of domestic discharge and to investigate the eventual ”limiting factors”. Finally this paper aims to study the effect on the secondary effluent of tertiary treatment carried out artificially in the laboratory.

The mechanical effects of water flow on fish eggs and larvae

The impact of mechanical stresses upon ichthyoplankton entrained in power plant cooling systems has long been considered negligible. Arguments and evidence exist, however, to show that such a supposition is not universally true, especially in nuclear power plants. The mechanisms of mechanical damage can be detailed in terms of pressure change, acceleration, and shear stress with in the fluid flow field. Laboratory efforts to quantify the effects of mechanical stress have been very sparse. A well-planned bioassay is urgently needed. (PDF has 11 pages.)

Towed vehicles: undulating platforms as tools for maping coastal processes and water quality assessment, Seaside, California, February 5-7,2007. Workshop proceedings

The Alliance for Coastal Technologies (ACT) Workshop on Towed Vehicles: Undulating Platforms As Tools for Mapping Coastal Processes and Water Quality Assessment was convened February 5-7,2007 at The Embassy Suites Hotel, Seaside, California and sponsored by the ACT-Pacific Coast partnership at the Moss Landing Marine Laboratories (MLML). The TUV workshop was co-chaired by Richard Burt (Chelsea Technology Group) and Stewart Lamerdin (MLML Marine Operations). Invited participants were selected to provide a uniform representation of the academic researchers, private sector product developers, and existing and potential data product users from the resource management community to enable development of broad consensus opinions on the application of TUV platforms in coastal resource assessment and management. The workshop was organized to address recognized limitations of point-based monitoring programs, which, while providing valuable data, are incapable of describing the spatial heterogeneity and the extent of features distributed in the bulk solution. This is particularly true as surveys approach the coastal zone where tidal and estuarine influences result in spatially and temporally heterogeneous water masses and entrained biological components. Aerial or satellite based remote sensing can provide an assessment of the aerial extent of plumes and blooms, yet provide no information regarding the third dimension of these features. Towed vehicles offer a cost-effective solution to this problem by providing platforms, which can sample in the horizontal, vertical, and time-based domains. Towed undulating vehicles (henceforth TUVs) represent useful platforms for event-response characterization. This workshop reviewed the current status of towed vehicle technology focusing on limitations of depth, data telemetry, instrument power demands, and ship requirements in an attempt to identify means to incorporate such technology more routinely in monitoring and event-response programs. Specifically, the participants were charged to address the following: (1) Summarize the state of the art in TUV technologies; (2) Identify how TUV platforms are used and how they can assist coastal managers in fulfilling their regulatory and management responsibilities; (3) Identify barriers and challenges to the application of TUV technologies in management and research activities, and (4) Recommend a series of community actions to overcome identified barriers and challenges. A series of plenary presentation were provided to enhance subsequent breakout discussions by the participants. Dave Nelson (University of Rhode Island) provided extensive summaries and real-world assessment of the operational features of a variety of TUV platforms available in the UNOLs scientific fleet. Dr. Burke Hales (Oregon State University) described the modification of TUV to provide a novel sampling platform for high resolution mapping of chemical distributions in near real time. Dr. Sonia Batten (Sir Alister Hardy Foundation for Ocean Sciences) provided an overview on the deployment of specialized towed vehicles equipped with rugged continuous plankton recorders on ships of opportunity to obtain long-term, basin wide surveys of zooplankton community structure, enhancing our understanding of trends in secondary production in the upper ocean. [PDF contains 32 pages]

Ground water-surface water interactions sensor technology, Savannah, Georgia, March 7-9, 2005: workshop proceedings

The Alliance for Coastal Technologies (ACT) held a Workshop on Sensor Technology for Assessing Groundwater-Surface Water Interactions in the Coastal Zone on March 7 to 9,2005 in Savannah, GA. The main goal of the workshop was to summarize the general parameters, which have been found to be useful in assessing groundwater-surface water (GW-SW) interactions in the coastal zone. The workshop participants (Appendix I) were specifically charged with identifying the types of sensor systems, if any, that have been used to obtain time-series data and to make known which parameters may be the most amenable to the development/application of sensor technology. The group consisted of researchers, industry representatives, and environmental managers. Four general recommendations were made: 1. Educate coastal managers and agencies on the importance of GW-SW interactions, keeping in mind that regulatory agencies are driven by a different set of rules than researchers: the focus is on understanding the significance of the problem and providing solutions. ACT could facilitate this process in two ways. First, given that the research literature on this subject is fairly diffuse, ACT could provide links from its web site to fact sheets or other literature. Second, ACT could organize a focused meeting for managers and/or agency groups. Encourage development of primary tools for quantifying flow. The most promising technology in this respect is flow meters designed for flux chambers, mainly because they should be simple to use and can be made relatively inexpensively. However, it should be kept in mind that they provide only point measurements and several would need to be deployed as a network in order to obtain reliable flow estimates. For evaluating system wide GW-SW interactions, tools that integrate the signal over large areas would be required. Suggestions include a user-friendly hydrogeologic models, keeping in mind that freshwater flow is not the entire story, or continuous radon monitors. Though the latter would be slightly more difficult to use in terms of background knowledge, such an instrument would be low power and easy to operate and maintain. ACT could facilitate this recommendation by identifying funding opportunities on its web site and/or performing evaluations of existing technologies that could be summarized on the web site. (pdf contains 18 pages)

Commercial pond fish culture using waste water

Waste water from some National Electric Power Authority (NEPA) housing units in Nigeria was fed to a 0.4 ha pond which was stocked with 2,200 Sarotherodon galilaeus fingerlings with a mean weight of about 36.0gm and 1000 Cyprinus carpio fingerlings with a mean weight of 10gm. This yielded after 10 months, over 2300 kg of harvestable fish plus over 20,000 Sarotherodon galilaeus fingerlings. The growth rate of C. carpio was not very encouraging possibly because of the type of plankton that colonised the pond. The S. galilaeus became stunted because of overpopulation as there were no carnivores to control their excessive breeding. The physico-chemical parameters were favourable for the growth of fish food organisms

Ecosystem study Altenwoerth: impacts of a hydroelectric power-station on the River Danube in Austria

The aim of this article is to briefly describe the effects of the Altenwoerth Barrage, on the River Danube, on some physical variables and their consequent effects on water chemistry and the biota of the river. The methods used for biological sampling are summarised, especially those used in the limnological part of the study, and the macroinvertebrate and fish fauna listed. Comparisons are then made between the impounded section of river immediately above the dam and two unimpounded free-flowing sections of the river. Further developments on the Danube are considered.

The predicting power of models for eutrophication

Restoration of water-bodies from eutrophication has proved to be extremely difficult. Mathematical models have been used extensively to provide guidance for management decisions. The aim of this paper is to elucidate important problems of using models for predicting environmental changes. First, the necessity for a proper uncertainty assessment of the model, upon calibration, has not been widely recognized. Predictions must not be a single time trajectory; they should be a band, expressing system uncertainty and natural variability. Availability of this information may alter the decision to be taken. Second, even with well-calibrated models, there is no guarantee they will give correct projections in situations where the model is used to predict the effects of measures designed to bring the system into an entirely different ”operating point”, as is typically the case in eutrophication abatement. The concept of educated speculation is introduced to partially overcome this difficulty. Lake Veluwe is used as a case to illustrate the point. Third, as questions become more detailed, such as ”what about expected algal composition”, there is a greater probability of running into fundamental problems that are associated with predicting the behaviour of complex non-linear systems. Some of these systems show extreme initial condition sensitivity and even, perhaps, chaotic behaviour, and are therefore fundamentally unpredictable.

Impact of dead and sunken water hyacinth on biotic communities, the aquatic environment and socio-economic activities

The mobile water hyacinth, which was produced in growth zones, especially Murchison Bay, was mainly exported to three sheltered storage bays (Thruston, Hannington and Waiya). Between 1996 and May 1998, the mobile form of water hyacinth occupied about 800 ha in Thruston Bay, 750 ha in Hannington Bay and 140 ha in Waiya Bay). Biological control weevils and other factors, including localised nutrient depletion, weakened the weed that was confined to the bays and it sunk around October 1998. The settling to the bottom of such huge quantities of organic matter its subsequent decomposition and the debris from this mass was likely to have environmental impacts on biotic communities (e.g. fish and invertebrate), physico-chemical conditions (water quality), and on socio-economic activities (e.g. at fish landings, water abstraction, and hydro-power generation points). Sunken water. hyacinth debris could also affect nutrient levels in the water column and lead to reduction in the content of dissolved oxygen. The changes in nutrient dynamics and oxygen levels could affect algal productivity, invertebrate composition and fish communities. Socio-economic impacts of dead sunken weed were expected from debris deposited along the shoreline especially at fish landings, water abstraction and hydropower generation points. Therefore, environmental impact assessment studies were carried out between 1998 and 2002 in selected representative zones of Lake Victoria to identify the effects of the sunken water hyacinth biomass

On the fishing power of monofilament and multifilament gill nets

The authors have discussed the results of comparative fishing, conducted in the Govindsagar reservoir, with simple monofilament and multifilament gill nets. The experiments were conducted both in clear and turbid water. In both these water masses, the monofilament gill net has been found to be more efficient. It is also found that the four major species of fishes of the reservoir have not shown any preference towards a specific gear.

Modified water spray chumming system for pole and line fishing of tuna

A water spray chumming system consisting of a 65 x 50 mm centrifugal pump driven by the propulsion engine through a PTO clutch and 'V' pulley power transmission system has been developed for the pole and line fishing of tuna. Water is sprayed through pipe loop system fitted on the edge of the fishing platform of the boat through small holes. The distance of the spray length can be adjusted by controlling the flow of the pump discharge water through a wheel valve.

The water hyacinth problem and the biological control option in the highland lake region of the upper Nile basin: Uganda's experience

The rapid proliferation and extensive spread of water hyacinth Eichhornia crassipes (Mart) Solms in the highland lakes of the Nile Basin within less than 15 years of introduction into the basin in the 1980s pauses potential environmental and social economic menace if the noxious weed is not controlled soon. The water weed has spread all round Lake Victoria and, in Uganda where infes tation is mos t severe, water hyacinth estimated at 1,330,000 ton smothers over 2,000 ha of the lakeshore (August,1994). Lake Kyoga which already constantly supplies River Nile with the weed is infested with over 570 ha, while over 80% of the river course in Uganda is fringed on either side with an average width of about 5m of water hyacinth. As the impact of infestation with water hyacinth on water quality and availability, transportation by water, fishing activities, fisheries ecology, hydro-power generation etc becomes clear in Uganda, serious discussion is under way on how to control and manage the noxious weed. This paper pauses some of the questions being asked regarding the possible application of mechanical and chemical means to control the water weed.Uganda has already initiated the use of biological control of water hyacinth on Lake Kyoga with a strategy to use two weevils namely Neochetinabruchi and Neochetina eichhorniae. The strategy to build capacity and infrastructure for mass multiplication and deployment of biological control of the weevils in the field developed in Uganda by the Fisheries Research Insti tu te (FIRI) and the Namulonge Agricultural and Animal production Research Insti tute (NAARI) is proposed in outline for evaluation. Plans to deploy this strategy on lake Kyoga are under way

Capture fisheries in Uganda: why Bujagali hydro-power project and ecological monitoring?

Human use of water resow-ces in Uganda has grown and intensified along with population growth and increasing demand to meet the diverse human needs. In the case of Uganda's rivers, the main uses include fisheries, hydropower generation, abstraction for potable water supply, discharge of sewage and navigation. All these uses can disrupt the integrity of the aquatic ecosystem and may affect the survival of the diversity of organisms. In consideration of the need to increase electricity to meet demand, the Bujagali Hydro-power Project (BHPP) and the National Environment Management Authority (NEMA) recognised the importance of safeguards to mitigate impacts of the project. The National Fisheries Resources Research Institute (NaFIRRI) was assigned the role of providing baseline information on the aquatic ecosystem of the Upper Victoria Nile and to follow up the findings with a monitoring framework during construction and post-commissioning phases.

Aquatic and fisheries survey of the upper Victoria Nile: a report prepared for AES Nile Power Bujagali hydropower project, final report

The aquatic ecosystem of the Upper Victoria Nile is part of a wider complex of water bodies (lakes and rivers) in Uganda that is of immense socioeconomic importance, especially the fisheries. A source of food, income, energy, irrigation and drinking water, the protection, sustainable use and management of the Upper Victoria Nile water resources are vital to Uganda's economy. The Upper Victoria Nile,due to its abundance of socio-economic benefits,provides a significant contribution to Uganda's economy. The fisheries contribute to the sector as a major source of the export earnings, second to coffee (NEMA,1996), sustain small fishing villages,provide income and generally improve nutrition. Apart from the socio-economic significance of the fisheries,the riverine features of the Upper Victoria Nile, especially its hydropower potential,distinguish this river from the rest of the aquatic ecosystems in the country.

The contribution and status of physical removal in sustainable management of water hyacinth

Physical control of water hyacinth consists of removing the plants from the water by hand or machines. It is considered over effetive because it involves removing the whole plants from water. The first attempt on physical control was in 1992 when weed infestation was causing serious problems to the fishing communities in Lake Kyoga. The fishermen had problems of accessing the lake as huge masses of mobile weed blocked landing sites. Furthermore, the fishers lost their nets, which were swept away by mobile water hyacinth. As a result, an integrated control strategy involving physical control (manual and mechanical removal) was put in place. Through this method, the fishers were able to open up access routes to fishing grounds even though weed mats often reblocked the access routes. In the infested lakes, manual removal offered remedial relief to fish Iandings and other access sites. Sites of strategic importance such as hydro-electric power generation dam, water intake points and docking points which had large masses of water hyacinth required heavy machinery and mechanical harvesters were used at these sites.

Impact of dead and sunken water hyacinth on biotic communities, the aquatic environment and socioeconomic activities

The mobile water hyacinth, which was produced in growth zones, especially Murchison bay, was mainly exported to three sheltered storage bays (Thruston, Hannington and Waiya). Between 1996 and May 1998, the mobile form of water hyacinth occupied about 800 ha in Thruston bay, 750 ha in Hannington bay and 140 ha in Waiya bay). Biological control weevils and other factors, including localised nutrient depletion, weakened the weed that was confined to the bays and it sunk around October 1998. The settling to the bottom of such huge quantities of organic matter its subsequent decomposition and the debris from this mass was likely to have environmental impacts on biotic communities (e.g. fish and invertebrate), physico-chemical conditions (water quality), and on socio-economic activities (e.g. at fish landings, water abstraction, and hydro-power generation points). Sunken water hyacinth debris could also affect nutrient levels in the water column and lead to reduction in the content of dissolved oxygen. The changes in nutrient dynamics and oxygen levels could affect algal productivity, invertebrate composition and fish communities. Socio-economic impacts of dead sunken weed were expected from debris deposited along the shoreline especially at fish landings, water abstraction and hydropower generation points. Therefore, environmental impact assessment studies were carried out between 1998 and 2002 in selected representative zones of Lake Victoria to identify the effects of the sunken water hyacinth biomass.