Eindhoven University of Technology MASTER What are the costs of wetland production? : integrating the environmental effect chain and the total economic value for a coastal wetland in Ghana van Stiphout, M.W.A. Award date: 2002 Link to publication Disclaimer This document contains a student thesis (bachelor's or master's), as authored by a student at Eindhoven University of Technology. Student theses are made available in the TU/e repository upon obtaining the required degree. The grade received is not published on the document as presented in the repository. The required complexity or quality of research of student theses may vary by program, and the required minimum study period may vary in duration. 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Romijn Eindhoven University of Technology, Faculty of Technology Management Ir. F.L.P. Hermans Eindhoven University of Technology, Centre Technology for Sustainable Development Prof. dr. A. Szirmai Eindhoven University of Technology, Faculty of Technology Management ii Executive Summary Setting Ghana has a lot of coastal wetlands, some of which are under severe environmental pressure. This contributes to the pollution of the Gulf of Guinea, but is also bad at itself because lagoons, or wetlands in general, are important ecosystems, because of their productivity and biodiversity. Their economic value is often not recognised because a great deal of their value is not expressed in markets. If these values are calculated, and combined with knowledge on the environmental situation, the lagoons can be managed more wisely. Goal Our goal is to determine the economic value and investigate how it is related to human activities, environmental pressure and environmental quality. An integrated study of all of these aspects should give better insight into the threats and development options of the economic value. Theoretical framework A general model exists to study the total economic value of an ecosystem, and the relation with the functions, uses and goods & services it provides. A framework for studying environmental effects of human activities also exists, known as the environmental effect chain. We have combined the two models, to construct a framework that allows us to study the total economic value and its relation to human activities, environmental pressure and environmental quality in an integrated manner. Quantification of the environmental pressure and quality will enable us to identify to what extend the economic value that is threatened. This framework is shown in the following figure: -----------------------------------, Needs of Environ­ Environ­ stake­ General mental mental holders Activities pressure Quality r ------------ Lagoon - us mg Environmental activities Goods & services Total Economic Value Lagoon Catchment Area Figure E.1: Theoretical framework iii In order to answer the research question we first have to assess the concepts in the framework and their mutual relationships. Not all the concepts and relations are studied to the same extent. Besides the determination of the Total Economic Value through special techniques, we have focused on the pollution and erosion (both forms of environmental pressure) and their influence on the environmental quality. Since direct data on pollution were not available, we assessed it by relating it to the human activities, through the Rapid Assessment Method. The relation between the environmental pressure and the environmental quality was studied extensively, as a way to model the behaviour of pollutants in the lagoon, a way to check the data from the Rapid Assessment Method, and a way to gain information on the level of siltation, on which no other data were present. Results As a case study we have chosen the Sakumo lagoon, near Terna. It is quite a small 2 lagoon (between 1 and 3.5 km ), with quite a large effective catchment area (127 2 km ). Of the activities that are going on there, housing is the most polluting, especially with respect to BOD, while for nutrients also agriculture is important. Industrial pollution is very small. Erosion is a very big problem, mainly caused by the construction activities, farming and illegal sand-winning in the catchment area. The results, which are obtaine d by combining information from the Rapid Assessment and the hydrologic and mass balances, are shown in the following list: BOD waste load: 121 tonnes/year Total N waste load : 90 tonnes/year Total P waste load: 8.5 tonnes/year Total SS waste load: 2, 000 tonnes/year Total Sediment yield: 8,000 tonnes/year Despite these loads the water quality is not bad, and there is enough oxygen in the water. The nutrient levels are high in the rainy season, when there is a lot of run-off, but recover during the rest of the year. By combining data from the Rapid Assessment and the mass balance for Suspended Solids, we have made a rough estimate for the level of siltation. The decrease in surface area is 0.16% per year. The fish in the lagoon is in bad shape, and has decreased in size because of over­ exploitation. Concerning the economic value, the most important goods are water for agriculture and fish. There is also a very important non-use value, which is the value the lagoon has to the international community l:ecause it is a breeding site for rare bird species. In total the lagoon is worth around $ 432,000. This seems quite a lot, but the value per hectare is much lower than the value of agricultural land (315 $/ha compared to 1, 700 $/ha for rain-fed farming). The pollution of the Sakuma lagoon is not a problem (yet). Erosion is a problem as it causes the lagoon to silt up. The fish resources of the lagoon are over-exploited. Since the water quality is quite good, most of the goods & services are not threatened Only fish is directly threatened; over-exploitation and siltation are expected to decrease the yield. Whether this will cause the value of fish to decrease is hard to predict since scarce supply of fish might also cause the value to increase. iv Fishermen are thus threatening the goods on which they depend. This also goes for farmers although their threat is less direct. Both groups are also the ones with the lowest income among the stakeholders, and are thus the most vulnerable. Policies that focus on these groups and the threats they cause are thus likely to give high returns, and are likely to be successful. v Shout-outs According to an old Chinese saying everything there is to know is somewhere in the universe, the art is only to find it. During my the sis I certainly practised the art, since the majority of the research consisted of finding the right reports. It made me wonder whether I was actually doing anything, or just rearranging the data that were floating around in the universe. It was a turbid miverse I was working in, and finding the right information was at times more difficult than any old Chinese could have imagined. It did not bother me, however, because it would have been terribly boring to spend five months in a library in Ghana. As my fellow -exchange-student complained about the uselessness of the libraries I decided not to bother and prepare for a quest. I bought an All Terrain Bike, and visited every person in and around Accra that might know something about my research subject. It was interesting and entertaining, as I visited all kinds of institutes and met with all kinds of people that gave me a nice insight into the Ghanaian life. Talking about the subject and discussing the relevance gave me the feeling that I was actually working, and learning. Some days were more successful than others, but as time passed by I obtained almost every report that was ever written on the Sakumo lagoon. This report is the result of my quest, and naturally I owe a lot to the people that helped me during the quest. First of all I want to thank everybody at the Water Research Institute, where I did my research, for the kindness with which they received me. I am especially grateful to Dr. Charles Biney for his advice and support. The first part of the quest took place within the institute, and I thank Mrs. Asmah, Mr. Tumbulto, Mr. Baah, Mr. Akrasie, Mr. De Graft-Johnson, Dr. Abban, Mr. Dankwa and Mr. Asante for their help and advice. Outside of the Institute I want to thank everybody who was so kind to assist me, but special thanks go to Mr. Amankwah of the Wildlife Department, for all his assistance and advice that improved the quality of my work, to Dr. Gordon of the University of Ghana, to professor Dorm-Adzobu and Dr. Adorn of the Water Resources Commission, to Mr. Wise Amatefe of the Hydrological Services Department, Mr.