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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

A Comparison of Ecosystem Structure and Processes in Native and Non-native Cattail-dominated Wetlands

Rudolf, Melanie E. 01 October 2018 (has links)
No description available.
272

Per- and polyfluoroalkyl substances in surface water and Bluegill and its relationship to swimming performance and histology

Coy, Carrie 04 May 2020 (has links)
No description available.
273

Genetic Analysis of Marsh Spot Resistance in Cranberry Common Bean (Phaseolus vulgaris L.)

Jia, Bosen 22 August 2022 (has links)
Cranberry common bean (Phaseolus vulgaris L.) is planted worldwide and consumed as a critical food source of human protein, fibre, carbohydrates, and minerals. Marsh spot (MS) is a physiogenic disorder which severely impacts seed quality in common beans. Previous studies indicate that MS involves a nutritional disorder caused by Mn deficiency. However, the inheritance and genetic mechanism of MS resistance are still not fully understood. To investigate the genetics of MS resistance, a population of 138 recombinant inbred lines (RILs) was developed from a bi-parental cross between a susceptible cultivar Messina and a resistant cultivar Cran09. The population and its two parents were evaluated for MS resistance during five consecutive years from 2015 to 2019 in both sandy and heavy clay soils in Morden, Manitoba, Canada. The severities of MS were rated and subsequently converted to MS resistance index (MSRI) and MS incidence (MSI). Statistical analyses indicated that MSI and MSRI were highly correlated (r = 0.96-0.99) and had high broad-sense heritability (H²) of 86.5% and 83.2%, respectively. Joint segregation analysis (JSA) of 18 phenotypic datasets from five years and two soil types showed that MS resistance was controlled by four major genes with genetic interactions - one of which may suppress the additive effect of the other three genes. To identify the quantitative trait loci (QTL) and the candidate genes associated with the MS resistance, the 138 RILs and the two parents were sequenced using genotyping by sequencing approach. A total of 52,676 SNPs were detected. After further filtering with a threshold of minor allele frequency > 0.01 and call rate > 20%, 2,061 SNPs were retained and then imputed for genetic map construction and QTL mapping. A genetic map consisting of 2,058 SNP markers on 11 linkage groups or chromosomes was constructed, which covered 1,004 recombination blocks with a total length of 6,449 cM and an average block of 6.42 cM. Three linkage map-based QTL-mapping models ICIM-ADD, ICIM-EPI, and GCIM and one genome-wide association study (GWAS) model RTM-GWAS for 18 phenotypic datasets from different years and soil types were used for identification of QTL. A total of 36 QTL, including 21 of additive and 15 of epistatic effects, were identified. Functional gene annotation analysis revealed 151 Mn-related candidate genes across the common bean reference genome and 17 of them harbored the six QTL discovered in this study. In conclusion, MS resistance in common bean is a highly heritable trait and controlled by several major and minor genes. The results of JSA and QTL mapping advance the current understanding of the genetic mechanisms of MS resistance in cranberry common bean, and provide additional resources for application in genomics-assisted breeding and potential isolation and functional characterization of the candidate genes.
274

Profound Possibilities: Microscopic Science and the Literary Imagination, 1820-1900

Carmack, Jeremy 10 November 2022 (has links)
No description available.
275

Carbon Budgets of Created Riverine Wetlands in the Midwestern USA

Waletzko, Evan James 06 June 2014 (has links)
No description available.
276

Denitrification and a Nitrogen Budget of Created Riparian Wetlands

Batson, Jacqulyn A. 02 November 2010 (has links)
No description available.
277

Seasonal Fish Community use of the Great Lakes Coastal Marsh Coates Paradise as reproductive habitat

Theÿsmeÿer, Tÿs 08 1900 (has links)
<p>Coates Paradise is a 250 ha coastal marsh, located at the western most point of Lake Ontario, adjoining Hamilton Harbour. Currently the marsh is severely degraded. Only 15% of the marsh remains vegetated, while the rest exists as an open water turbid bay. Stresses affecting the marsh include a very high carp population, excessive nutrient and sediment input, and water level regulation. Both Coates Paradise and Hamilton Harbour are the targets of an extensive remediation plan, known as the Hamilton Harbour Remedial Action Plan (HHRAP 1991 ).</p> <p>Coastal marshes are recognized for their importance as reproductive areas for the fish community. Considering the importance of marshes to fish, there is a surprising lack of information available. There have been very few comprehensive studies of whole fish communities and their use of marshes, and even fewer which address reproductive utilization. Herdendorf et. al. (1986) listed fish community structure and utilization of marshes for spawning, nursery and feeding areas as the top priorities of coastal wetland research.</p> <p>This study examines the fish community of Coates Paradise for the purpose of providing detailed information on the fish community in association with the HHRAP, as well as examining fish community use of the marsh with respect to reproductive utilization.</p> <p>The study included both temporal and spatial coverage of the marsh fish community. In an attempt to capture whole fish community data for Coates Paradise, fish community surveys were done monthly during the ice-free portion of the season. Surveys were initiated in the summer of 1994, followed by 3 full seasons between 1995 and 1997. Further to this, Coates Paradise was subdivided into 3 habitat types including off-shore, near-shore, and lower river. These habitats were further subdivided into sub-habitats, based on habitat variables that included wind fetch, nutrient enrichment, and degree of vegetation. A total of 8 sub-habitat types were included. Within each sub-habitat type four 50 m transects were located. The transects were surveyed by electrofishing.</p> <p>A total of 47,512 fish covering 47 species were captured in the study. Annual species diversity averaged 38 species, while monthly richness followed a seasonal trend with a maximum of 34 species occurring in July. Most species of fish were found to exist only in the near-shore habitat. Also the near-shore habitat had substantially more fish (Exposed sub-habitat -187 I transect) than the off-shore habitat (Bay sub-habitat -8 I transect).</p> <p>All species demonstrated migration into and out of the marsh in association with spawning periods and spawning habitat guilds. Most species of non YOY fish had highest densities at corresponding spawning times and in correlation to spawning habitat guilds. Habitat preferences of YOY species also generally reflected a species spawning habitat guild. Total non YOY populations were also generally at a peak during spawning periods. The non YOY of most species showed a distinct migration out of the marsh following spawning periods. Samples taken two months prior to a species spawning periods had almost no fish of the species occurring in the marsh, while samples taken two months following peak spawning periods resulted in almost no larger fish of a species being found in the marsh.</p> <p>The dominant fish species of the marsh was adult carp. In the electrofishing data, adult carp represented 90% of the biomass, but only 10% of the total catch. Only six other species had substantial adult population, while most other species are represent by less than 15 individuals in the data set. These six species included, brown bullhead, white sucker, gizzard shad, white perch, spottail shiner and pumpkinseed, and are reflective of the state of the harbour (the adult habitat).</p> <p>The most abundant species in the marsh include YOY of gizzard shad, white perch and spottail shiners, reflecting the marsh's role as reproductive habitat. Maximum numbers of fish occurred in late August, with as many as 800 fish being captured in a single transect. At this time the fish community consisted almost entirely of YOY fish.</p> / Master of Science (MSc)
278

A Study of Certain Organic Compounds of the Bottom Sediments of the Dundas Marsh, Hamilton, Ontario

Larner, Elizabeth Anne 09 1900 (has links)
In the course of a little over a year, from January, 1950, to March, 1951, core samples of bottom sediments were collected at three different stations in the Dundas Marsh, Hamilton, Ontario. A number of the samples were analysed for total carbon content, bitumen, pectins, hemicelluloses, and cellulose and lignin content. This study is part of a larger investigated by the Department of Zoology to ascertain the relationships between the biological productivity in lakes and the rate of mineralization of the organic detritus in lake bottom sediments. / Thesis / Master of Science (MSc)
279

The influence of bottom-up effects on trophic cascades : a case study of Orchestia (Amphipoda) affecting redshank (Tringa totanus) predation risk in a saltmarsh ecosystem

Kenworthy, Nigel January 2018 (has links)
Previous research into bottom-up processes on saltmarshes has mainly focused on the influence of plant succession on herbivores. This study will present original research exploring the influence of bottom-up processes in a saltmarsh ecosystem between three trophic levels: Orchestia, redshanks, and sparrowhawks. Density dependence, may be the dominant top-down effect when higher numbers of sparrowhawks and redshanks are present, and may mask top-down and bottom-up trait effects which are constant. Bottom-up effects begin to emerge when cold conditions force redshanks from muddy creeks onto the saltmarsh to forage for Orchestia, because their primary prey, Corophium become less available. Larger flocks form and feeding on Orchestia requires them to balance a need to profit from the best available feeding patches and to be vigilant to sparrowhawk attack. Redshank vulnerability is compounded, because Orchestia hide in cold temperatures, so probing in the soil with their heads down makes them more vulnerable to sparrowhawk attack. Larger flocks may be able to exploit areas closer to sparrowhawk-concealing cover at the terrestrial boundary because they feel safer in greater numbers. Warmer temperatures make Orchestia more active which attracts redshanks, which can simultaneously feed and be vigilant because they peck and catch crawling and jumping Orchestia with their heads up. Consequently, increased flock size may temporarily depress Orchestia abundance, so that redshanks become spaced, leaving isolated individuals more vulnerable to attack. Therefore, it is a temperature-dependent bottom-up process which impacts upon both Orchestia and redshank behaviour, which then may influence the hunting success of sparrowhawks. Whether the characteristics of this saltmarsh ecosystem and the trophic dynamics can be compared to other examples is questionable. Saltmarshes probably differ in their topography and the way in which environmental conditions affect them that then defines which species are present and how these species interact.
280

Strategic Environmental Assessment Pre-Study of That Luang Marsh : For Sustainable Development in Vientiane Capital, Lao PDR

Olsson, Fredrik January 2010 (has links)
IntroductionLao People Democratic Republic (Lao PDR / Laos) has a population of 5.8 million people and is today one of the least developed countries in Asia. That Luang Marsh (TLM) is the largest remaining urban wetland (2000 hectare) in Vientiane Capital, which historically has supplied wildlife and local people with several eco-services. Some important functions are wastewater treatment, flood control (water storage), and several agricultural and aquacultural services. Due to the flat landscape and the low permeability in soil, the area becomes naturally flooded during the wet season when the water level in the Mekong River is high. All storm water in Vientiane is drained through TLM. There have been several projects in Vientiane aimed to solve the drainage and sanitarian situation. However, the problems have still not been completely solved today. Aim and objectives This Master of Science thesis aims at providing a prestudy for a Strategic Environmental Assessment (SEA), which may be used for creating a full-scale SEA in the future. The main objectives that will be analyzed are: Wastewater treatment in Vientiane. The environmental impact caused by human activity and how it can be reduced in TLM / Vientiane / Mekong River. Sustainable development in Vientiane. The need of SEA in TLM. Flood control in Vientiane. • Agriculture and aquaculture in Vientiane. The WATER Project and New Town Development Project. Socioeconomic overview of Laos / Vientiane. Methodology This thesis is a collaboration between the Swedish university KTH and the Thai university AIT. The student (author of this report) was linked to Dr. Shipin, co-advisor at AIT through Dr. Frostell, supervisor at KTH, and Dr. Berg. A field study was made from October 2008 - December 2008 in Vientiane Capital, Laos. The student has collected information from NGOs, institutions, departments, laboratories, libraries, local people, and Internet in the form of hardcopy literature, electronic documents, e-mail contacts, and interviews. During two days the student had the favour to join a team sent out by WWF for collecting water samples around the marsh. The team consisted of representatives from WWF and the three districts that surround That Luang Marsh. Strategic Environmental Assessment The main purpose of a SEA is to support sustainable decision-making processes in an area. Except from environmental aspects, the SEA also considers socioeconomical aspects. SEAs may differ in terminology and practice between countries and organisations but do usually include stages like preliminary scan, conduction of SEA, preparation of the report, implementation of SEA in PPP (policy, plans, or programmes), and review of the implementation. This report gives a short briefing about how SEAs are produced by CIDA (Canadian International Development Agency) and according to the European Directive. The European Directive is the standard SEA for several European countries. The report does also present the project oriented EIA (Environmental Impact Assessment) Wetland valuation Wetlands may be valuated in different ways. This report explains one method where the valuation is separated into: DUV (Direct Use Value), IUV (Indirect Use Value), OV (Option Value), and NUV (Non Use Value). These are added to TEV (Total Economical Value). WATER Project The WATER project is a response to the environmental and socioeconomical problems that have occurred in Vientiane. Several past projects have been less successful, which have resulted in adverse impact on the society and the ecosystem. The WATER project tries to highlight the wetland values and convince authorities to use CWs (Constructed Wetlands) instead of conventional wastewater treatment plants for treating wastewater. This project will first do five pilot studies in Vientiane. Three will be used for treating domestic wastewater and two for industrial. The project is a part of the Wetland Alliance Programme. Main partners during the project are the government of Lao PDR, WWF Laos, WWF Germany, Wild Fowl &amp; Wetland Trust (WWT). Other involved partners are CORIN, AIT, WFC, CIDA, and Sida. It seems that the authorities will allocate 22 hectares for constructing a CW that will purify Vientiane’s most polluted urban water canal Hong Ke. The WATER Project recommends that even Hong Xeng is included which totally requires 61 hectare CW area. New Town Development Project The New Town Development is a collaboration between the Lao and Chinese government. The plan is to develop the city so it attracts more foreign and domestic investors. 1000 hectares low valued land will be developed for business and 200 hectare will be used for creating an artificial lake aimed for compensating lost wetland area. As a part of the negotiations, the Chinese has already constructed a stadium that was used during the SEA Games 2009. 670 hectare will be developed in TLM, 100 hectare in Dongphosy Forest, and 430 hectare close to the new stadium. The Chinese investors will lease the developed land for 50 years. This may be used for business. When the project period is over, the Lao government have the right to reclaim all developed land without compensation. The Chinese Suzhou City stands as model for the development project in Vientiane. The estimated cost of the project is USD 800-1000 million. Discussion and conclusions Choosing SEA, CEA (Cumulative Effect Assessment), or another strategic assessment method should not be the main issue. As long as the method contributes to a strategic sustainable development and is internationally accepted it may be used for PPPs. The main issue of SEA is not to create a report, but convincing authorities about the importance of sustainable decision-making processes. Factors that may inhibit a sustainable development in Laos are low education, corruption, and greedy investors that devastate the environment for own profit. The laws are in several cases enough but due to the lack of a judicial organization and economical funding the legislative system becomes inefficient. It is difficult to valuate wetlands. The greatest challenge is to valuate OVs and NUVs. OVs are difficult because they are just options. NUVs are based on a subjective estimation because these consider cultural and aesthetical values. A problem with the New Town Development Project is that some vulnerable groups that live in TLM will be forced to live in a resettlement area. These people may have difficulties to adapt to the new environment. It is important that the authorities work extra hard with helping project affected people. Wetland degradation is probably a result of i) intense water pollution (wastewater from households and industries), ii) physical destruction (housing, filling, and artificial drainage), iii) overuse of wetland VI resources, iv) invasions or invitations of new species (golden apple snail). In theory, wetlands may be replaced with modern technology for protecting the city against flooding. One way is to build a cement layer in Houay Mak Hiao River for increasing the drainage capacity. However, because the country has very small economical margins and the hydrological situation is not completely investigated, this could be treated as a risk project. Another problem is that the wastewater capacity will reduce and the biodiversity in the river will be lost. The loss of wastewater treatment needs to be compensated with modern technology. Something needs to be done for increasing the sanitarian situation in Vientiane. This report has compared the benefits of using conventional wastewater treatment plants and CWs. Probably the most reasonable solution is to use a CW for treating the wastewater in Hong Ke while the new centre in TLM uses a conventional wastewater treatment plant. This is an optimal solution because a conventional wastewater treatment plant for treating the water in Hong Ke would require a completely new sewage system, which could become very expensive. Maintaining a conventional wastewater treatment plant is also expensive and requires special trained staff. An easier alternative would be to use CWs for the old part of Vientiane. Because the new centre will be built in a modern style with new infrastructure this part of Vientiane could treat wastewater conventionally. Building a conventional wastewater treatment plant would also save some high-valuated land. Conventional Wastewater TreatmentAdvancedStandardizedQuick turnover timeRequire small spaceCould be more sanitarianProcesses better evaluated Constructed WetlandLong lifetimeEffective in warm climatesNo chemical inputEasy to maintainLow sludge productionAestheticalLess need to change infrastructureLow running cost (flat topography) The author will not decide if Vientiane should develop into a top modern city or remain as a small sized capital as it is today. However, today the situation is unsustainable and something needs to be done. Better organization and planning is necessary for not repeating mistakes that were made during past projects. All decisions have to be based on a non-corruptive process and sustainable thinking. Integrating an environmental and socioeconomical strategy into the future of Vientiane should be of interest for all Laotians. Vientiane is the economical centre of Laos and an increased discharge of polluted water into the Mekong would increase the stress of the important river. A collapse of the biodiversity in the Mekong would strike hard on Laos’ fishing industry and economy. Decisions made today will surely more or less affect people at local, regional, national, and international level in the future. / Inledning Mänsklig aktivitet har på vissa håll resulterat i en allvarlig miljöpåverkan. Laos har en befolkningsmängd på 5,8 miljoner invånare och räknas idag som ett av Asiens minst utvecklade länder. That Luang Marsh (TLM) är huvudstaden Vientianes största urbana våtmarksområde (2000 hektar). Våtmarksområdet bjuder på flertalet ekologiska tjänster som under historiens lopp gynnat både människor och djur. Några av dessa är naturlig vattenrening och översvämningsskydd (vattenlager). Våtmarken bidrar till ett rikt jordbruk och akvakultur. Under regnperioden stiger vattennivån i Mekongfloden så att området naturligt svämmas över. Dräneringen av Vientiane försvåras eftersom landskapet är platt och permeabiliteten i jorden är låg. Huvudsakligen flödar vattnet ut via TLM och floden Houay Mak Hiao innan det når Mekongfloden. Flertalet projekt har försökt effektivisera Vientianes dräneringseffektivitet och minska de sanitära problemen. Dock finns det en hel del kvar att göra. Syften och mål Detta examensarbete är en förstudie till en Strategic Environmental Assessment (SEA). Förstudien skulle kunna utnyttjas till uppbyggandet av en komplett SEA. Huvudområden som undersöks i denna rapport är: Vattenreningen i Vientiane. Den mänskliga miljöpåverkan och hur denna kan lindras i TLM / Vientiane / Mekongfloden. Hållbar utveckling i Vientiane. Behovet av SEA i TLM. Översvämningsskydd i Vientiane. Jordbruk och akvakultur i Vientiane. Projekten WATER Project och New Town Development Project. En socioekonomisk översikt för Laos /Vientiane. Metod Projektet är ett samarbete mellan det svenska universitet KTH och det thailändska universitet AIT. Författaren till denna rapport, Fredrik Olsson är mastersstudent på KTH och har genomfört och utvecklat projektet tillsammans med handledaren Dr. Frostell, KTH och bihandledaren Dr. Shipin, AIT. Även Dr. Berg har haft en viktig roll i utvecklandet och det praktiska genomförandet av projektet. Oktober 2008 – december 2008 genomfördes fältstudier i Vientiane, Laos. Fakta till rapporten inhämtades främst från NGOs (Non- Governmental Organizations), institutioner, laboratorier, bibliotek, lokalbefolkning och internet. Detta skedde i form av tryckta papper/avhandlingar, elektroniska dokument, e-mail kontakter samt intervjuer. Under två dagar genomfördes fältstudier i TLM i samarbete med WWF. Syftet var att mäta vattenkvaliteten i våtmarken på ett antal förutbestämda platser. Gruppen bestod av en representant från WWF samt representanter från de tre distrikt som delar TLM. Strategic Environmental Assessment (Strategisk Miljöbedömning) Syftet med en SEA är att skapa hållbarhet i myndigheters beslutsprocesser. SEA integrerar både miljö och socioekonomiska aspekter i samma studie där målet är att sträva mot en hållbar utveckling. Olika SEA kan skilja sig i utformningen beroende på vilken handledning som används. Dock är dessa skillnader små och inträffar oftast i form av annorlunda terminologi och utförande. Normalt ingår moment som preliminär undersökning, genomförande av SEA, förberedelse av rapport, implementering av SEA i PPP (Policy, Plan och Program) samt utvärdering av implementeringen. Den här rapporten redovisar ytligt hur VIII en SEA genomförs enligt CIDA-modellen (Canadian International Development Agency) och enligt Europeiska Direktivet. Den senare handledningen används som standard i flertalet europeiska länder. Denna rapport kommer även att redovisa grunderna i EIA (Environmental Impact Assessment). Värdering av våtmarker Det finns ett antal olika sätt att värdera våtmarker. Ett sätt som redovisas i rapporten är att separera värderingsområdena till DUV (Direct Use Value), IUV (Indirect Use Value), OV (Option Value), och NUV (Non Use Value). Dessa summeras sedan till TEV (Total Economic Value). DUV beskriver de direkt synliga värdena av att bevara en våtmark, IUV de värden som är indirekta, OV de värden som kan vara möjliga i framtiden, NUV de värden som inte kan bedömas ur ett ekonomiskt och TEV våtmarkens sammanlagda värde. WATER Project Detta projekt är ett svar på de sanitära och ekologiska problemen som förekommer i Vientiane. Flertalet projekt har varit mindre framgångsrika vilket påverkat både samhället och ekosystemet negativt. För att råda bot på de sanitära problemen pågår för närvarande ett försök att informera myndigheterna om fördelarna med att bygga konstruerade våtmarker. Dessa skulle kunna vara ett alternativ till konventionella reningsverk. För att bevisa våtmarkernas effektivitet planeras nu byggandet av fem pilotanläggningar i Vientiane. Tre kommer användas för att rena kommunalt avloppsvatten medan två är avsedda för industriellt bruk. Projektet är en del av Wetland Alliance Programme. Samarbetspartners för WATER Project är laotiska staten, WWF Laos, WWF Tyskland och Wild Fowl &amp; Wetland Trust (WWT), CORIN, AIT, WFC, CIDA och Sida. Indikationer tyder på att konstruerade våtmarker (22 hektar) kommer att byggas för rening av vattnet i dräneringskanalen Hong Ke. Detta är Vientianes mest förorenade kanal. Dock önskar WATER Project att totalt 61 hektar avsätts så att även kanalen Hong Xeng kan renas. New Town Development Project Projektet är ett samarbete mellan den laotiska och kinesiska staten. Planen är att ett omfattande utvecklingsprojekt ska locka flera utländska och inhemska investerare till Vientiane. Totalt kommer 1000 hektar lågt värderad mark att kommersialiseras. Ytterligare 200 hektar kommer att användas till byggandet av en konstgjord sjö som kompenserar för förlorad våtmarksyta. Kineserna har i gengäld lovat att bygga en sportarena för SEA Games 2009. 670 hektar kommer exploateras i TLM, 430 hektar i närheten av den nya sportarenan och 100 hektar i Dongphosy skogen. Kinesiska investerare kommer att arrendera marken under 50 år. Under denna period kan investerarna fritt göra affärer och har rätt att sälja marken till vem de vill. När 50 år har passerat har den laotiska staten rätt att ta tillbaka den arrenderade marken utan kompensation. Som modell för utvecklingsprojektet står kinesiska Suzhou City. Projektet beräknas kosta 800-1000 miljoner amerikanska dollar. Diskussion och slutsats Det spelar ingen större roll vilken metod som används för att nå en hållbar utveckling om den har någon form av internationell acceptans, är strategisk och tar hänsyn till att integrera både miljö och socioekonomiska frågor i samma studie. SEA och CEA (Cumulative Effect Assessment) är endast några alternativ. Målet med en SEA är först och främst inte avsedd för att skapa en rapport utan snarare hållbarhet i beslutsprocesser på PPP-nivå. Faktorer som motverkar hållbar utveckling i Laos är bland annat korruption, dålig utbildning och giriga investerare som maximerar sina ekonomiska vinster på miljön och samhällets bekostnad. Det är svårt att värdera OV eftersom denna parameter endast tar hänsyn till möjliga framtida värden. Samtidigt är NUV näst intill omöjligt att värdera eftersom denna parameter värderar kulturella och etiska värden. Värderingen av NUV blir då en subjektiv bedömning. Under New Town Development Project kommer flertalet människor i TLM tvingas flytta till en mer urban miljö. Dessa grupper är ofta speciellt sårbara eftersom de har bristfällig kunskap om urbana arbeten. Det är extra viktigt att myndigheterna följer upp dessa människor så att deras lidande minimeras. Förstörelsen av våtmarker beror troligtvis på i) stor tillförsel av vattenföroreningar (kommunalt och industriellt avloppsvatten), ii) fysisk destruktion (husbyggen, utfyllnad och konstgjorda dräneringssystem), iii) överutnyttjande av våtmarksresurser samt iv) invasioner och införanden av främmande arter som till exempel ”golden apple snail”. Teoretiskt skulle det vara möjligt att ersätta våtmarker med moderna tekniska lösningar för att undvika översvämningar. En lösning skulle vara att floden Houay Mak Hiao beläggs med ett cementlager för att öka vattenflödet ut från Vientiane. Dock har landet mycket svårt att finansiera denna typ av projekt och efterkommande underhåll på grund av små ekonomiska marginaler i statens budget. Det är heller inte helt kartlagt hur hydrologin i området fungerar. Ett annat problem med denna typ av lösning är att Houay Mak Hiaos vattenreningskapacitet och biodiversitet går förlorad. Om projektet genomförs måste vattenrening ske på annat sätt. Den här rapporten har försökt jämföra fördelarna med att använda konstruerade våtmarker (CW) istället för traditionella vattenreningstekniker. Att använda CW för att rena vattenmassorna i Hong Ke (avloppsvatten från gamla Vientiane) är nog det enklaste och billigaste alternativet medan den nya stadsdelen i mitten av TLM skulle kunna utrustas med ett konventionellt reningsverk. Detta eftersom de utländska stadsutvecklarna antagligen kommer ha tillräckligt med medel och kunskap för att stödja modern vattenreningsteknik som rymmer inom New Town Development Project. Infrastrukturen för att använda konventionella reningsverk är inte tillräckligt utvecklad i resterande Vientiane så att bygga ett konventionellt reningsverk i dessa delar av staden kan bli kostsamt. Dock blir situationen en annan i den nya stadsdelen eftersom denna byggs upp från grunden. Eftersom marken beräknas få ett avsevärt högre marknadsvärde kommer antagligen modern reningsteknik spara en del yta. Fördelar med konventionella reningstekniker är att dessa allmänt är mer avancerade, standardiserade, har en snabb omsättningstid på avloppsvattnet, är mindre platskrävande och processerna i dessa verk är bättre kartlagda. Däremot kan CWanläggningar användas under en längre tidsperiod, de har en hög effektivitet i varma klimat, har låg slamproduktion, kräver mycket små tillsatser av kemikalier, är enkla att underhålla, är mer estetiska, kräver enklare infrastruktur och har en låg driftskostnad. Författaren till denna rapport kan inte avgöra om det bästa för staden är att utvecklas till ett modernt urbant komplex. Dock är den nuvarande situationen ohållbar och därför bör någon form av åtgärder vidtas. Om organisationen och planering inom och mellan projekt förbättras minskar risken för misslyckade projekt. Det är viktigt att alla beslut som fattas grundas på ett korruptionsfritt hållbarhetstänkande. Om Vientiane strävar mot att ta ett större ansvar för miljö och socioekonomi så kommer landet som helhet att gynnas, eftersom huvudstaden är motorn i Laos ekonomi. Ett ökat okontrollerat utsläpp av vattenföroreningar från Vientiane kommer att öka belastningen på Mekongfloden. En biodiversitetskollaps i Mekongfloden skulle få allvarliga konsekvenser för landets fiske och ekonomi. De beslut som fattas idag kommer i framtiden att mer eller mindre påverka människor på ett lokalt, regionalt, nationellt och internationellt plan.

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