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Characterization of sorghum [Sorghum bicolor (l.) Moench] parental lines and prediction of their hybrid performance under simulated water and population density stress.Karari, Clement Kamau. January 2006 (has links)
Sorghum breeders have not made much yield improvement in new sorghum varieties in
Kenya since Serena in was released in the late 1960s. KARI Mtama-1 which was released
in 1993 has no yield advantage over Serena. A yield plateau for sorghum in Kenya is
apparent. A new breeding approach was adopted to break that yield barrier. Development
of hybrid sorghum was proposed and is expected to break the yield barrier and also
deliver cultivars that meet farmers' main requirements. The objectives of the study were to
(1) identify farmers' requirements in sorghum cultivars, constraints to sorghum production
and why improved cultivars from research are not being adopted, (2) characterize male
and female parents and establish if genetic distance could identify superior parent
populations for hybrid production (3) estimate genetic variance components and
determine the possibility of using GCA and SCA estimates in choosing parents for use in
hybrid production, (4) test hybrids and open pollinated variety (OPV) parental lines for
stress tolerance and identify tolerant hybrids for further testing and, (5) compare single
cross hybrids and OPV varieties in yield performance. Participatory rural appraisal in
Kitengei and Nzambani areas of Kambu showed that sorghum was especially important in
semi-arid parts of Kenya. Food, trade, feed, nursing food and thatching were the most
important uses of sorghum. High grain and stover yield, large grain size, early maturity,
drought tolerance, pest and disease resistance, coloured grain and intermediate plant
height were the major requirements of farmers. Fifty-three pollinators and forty-one male
sterile parents were introduced from four sources and screened together with 27 pollen
parents from Kenya. Parents and hybrids were tested in 4 environments: high and low
plant density, in high and low moisture regimes laid out in a triple square lattice design in
Kenya, with parents having two additional tests in South Africa. Males, females, sexes and
parental sources differed significantly in head weight. There were sex x country and sex x
environment interactions for head weight. Genetically distant parents' populations had
higher chances of superior heterosis. Parents showed significant additive genetic variance
in head weight. The regression of non-additive to additive genetic variance was roughly
one and significant. Three female and five male parents were suitable for production of
hybrids adapted to multiple environments. Hybrids and OPV lines significantly varied in
head weight. Hybrids were superior to OPV lines in most agronomic traits. Economic
superiority of the hybrids was sufficient to cover cost of hybrid production and distribution
in Kenya. Hybrids and OPV lines varied significantly for plant density stress. Hybrids were
less sensitive to stress and more productive than OPV lines under population density
stress. KARI varieties were sensitive to plant density stress. In general low sensitivity to
stress was beneficial and hybrids had superior yield to inbred varieties. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.
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Field spectroscopy of plant water content in Eucalyptus grandis forest stands in KwaZulu-Natal, South AfricaJanuary 2008 (has links)
The measurement of plant water content is essential to assess stress and
disturbance in forest plantations. Traditional techniques to assess plant water
content are costly, time consuming and spatially restrictive. Remote sensing
techniques offer the alternative of a non destructive and instantaneous method of
assessing plant water content over large spatial scales where ground
measurements would be impossible on a regular basis. The aim of this research
was to assess the relationship between plant water content and reflectance data in
Eucalyptus grandis forest stands in KwaZulu-Natal, South Africa. Field reflectance
and first derivative reflectance data were correlated with plant water content. The
first derivative reflectance performed better than the field reflectance data in
estimating plant water content with high correlations in the visible and mid-infrared
portions of the electromagnetic spectrum. Several reflectance indices were also
tested to evaluate their effectiveness in estimating plant water content and were
compared to the red edge position. The red edge position calculated from the first
derivative reflectance and from the linear four-point interpolation method performed
better than all the water indices tested. It was therefore concluded that the red
edge position can be used in association with other water indices as a stable
spectral parameter to estimate plant water content on hyperspectral data. The
South African satellite SumbandilaSat is due for launch in the near future and it is
essential to test the utility of this satellite in estimating plant water content, a study
which has not been done before. The field reflectance data from this study was
resampled to the SumbandilaSat band settings and was put into a neural network
to test its potential in estimating plant water content. The integrated approach
involving neural networks and the resampled field spectral data successfully
predicted plant water content with a correlation coefficient of 0.74 and a root mean
square error (RMSE) of 1.41 on an independent test dataset outperforming the
traditional multiple regression method of estimation. The potential of the
SumbandilaSat wavebands to estimate plant water content was tested using a
sensitivity analysis. The results from the sensitivity analysis indicated that the xanthophyll, blue and near infrared wavebands are the three most important
wavebands used by the neural network in estimating plant water content. It was
therefore concluded that these three bands of the SumbandilaSat are essential for
plant water estimation. In general this study showed the potential of up-scaling field
spectral data to the SumbandilaSat, the second South African satellite scheduled
for launch in the near future. / Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2008.
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Variation in morphology, salinity and waterlogging tolerance and resource allocation in strawberry clover (Trifolium fragiferum L.) : implications for its use in mildly saline soils in southern Australian farming systemsMcDonald, Kathi January 2009 (has links)
[Truncated abstract] In southern Australian farming systems the replacement of deep-rooted perennial native vegetation with shallow-rooted annual crops and pastures has resulted in rising groundwater tables and an increased incidence of dryland salinity. It has been suggested that to address this issue by restoring hydrological balance, large areas of agricultural land need to be vegetated with perennial plants. One of the most agriculturally productive ways to do this is to introduce perennial pastures, both into upslope groundwater
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INFLUÊNCIA DOS NÍVEIS DE ÁGUA NA DINÂMICA DE MACRÓFITAS AQUÁTICAS EMERGENTES DO BANHADO DO TAIM / INFLUENCE OF WATER LEVELS IN THE DYNAMICS OF EMERGENT AQUATIC MACROPHYTES FROM TAIM WETLANDRosa, Cristiano Niederauer da 13 January 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work evaluated, throught techniques of Remote Sensing and geoprocessing, the influence of hydrological conditions in the dynamics of emergent aquatic macrophytes in Taim Wetland (TW), important wet area in Rio Grande do Sul. The TW covers about 53% of the entire area of Taim s Ecological Station, a Federal Protected Area, which has its uses shared, mainly between biodiversity protection and irrigation. The irrigation is an important economical activity for the region, however, it changes the hydrological regime of TW, a fundamental feature for the maintenance of local biodiversity. Thus, the understanding of how the hydrological regime impacts TW s biodiversity is an important tool for the management of water resources in the region. In this context, three species of emergent aquatic macrophytes (EAM), Z.bonariensis, S. californicus and S. giganteus, were selected, both considered as biological indicators of TW. In order to evaluate how the water levels impact the three EAM, some analyses on the relationship among the hydrological condition, maps of vegetation occurrence, index for normalized difference (IND) and index of habitat suitability (IHS) were carried out. For the identification of the occurrence areas and determination of IND of EAM, Landsat images from TM and ETM sensors were used, comprising the period between 1984 and 2003, while the IHS and the hydrological regime were obtained from previous studies (Tassi, 2008; Xavier, 2015). The employed methodology showed that the EAM Z.bonariensis and S. californicus are more sensitive to larger water levels (representatives of flood conditions); in this situation, reductions in the occurrence areas of these species were indentified. For smaller water levels (drought conditions), there was an increasing in the occurrence areas of the three species. The IND showed an effective index for the understanding of EAM s response to the hydrological conditions, although in many cases there was so much difficulty in the differentiation of vegetation and water. Generally, good coefficients of determination were found between the IND and the average IHS of three months (month of image + two months previous to the image date), and between the IND and the hydrological condition (water level) of two months previous to the image date. These results are the evidence that the effects of hydrological conditions on the studied EAM are not readily detected, and that anthropic actions can produce long-term effects. / O presente trabalho avaliou, por meio de técnicas de Sensoriamento Remoto e geoprocessamento, a influência das condições hidrológicas na dinâmica de macrófitas aquáticas emergentes no Banhado do Taim (BT), importante área úmida do Rio Grande do Sul. O BT ocupa cerca de 53% da área total da Estação Ecológica do Taim, uma Unidade de Conservação Federal, que tem seus usos compartilhados, principalmente entre conservação da biodiversidade e irrigação. A irrigação é uma importante atividade econômica para a região, no entanto, altera o regime hidrológico do BT, característica fundamental para a manutenção da biodiversidade local. Assim, o entendimento de como o regime hidrológico impacta a biodiversidade do BT constitui-se em uma importante ferramenta para o gerenciamento dos recursos hídricos da região. Neste contexto, foram selecionadas três espécies de macrófitas aquáticas emergentes (MAE), Z. bonariensis, S. californicus e S. giganteus, consideradas indicadores biológicos do BT. Para avaliar como os níveis de água impactam as três MAE, foram realizadas análises da relação entre condição hidrológica, mapas de ocorrência da vegetação, índice por diferença normalizada (NDVI) e índice de adequabilidade de habitat (IAH). Para a identificação das áreas de ocorrência e determinação do NDVI das MAE, foram utilizadas imagens Landsat dos sensores TM e ETM, compreendidas entre os anos de 1984 e 2003, enquanto o IAH e o regime hidrológico foram obtidos a partir de estudos prévios (Tassi, 2008; Xavier, 2015). A metodologia empregada mostrou que as MAE Z. bonariensis, S. californicus são mais sensíveis a níveis d água maiores (representativos de condições de cheia); nesta situação, foram identificadas reduções nas áreas de ocorrência destas espécies. Para níveis de água menores (condições de seca), houve um aumento nas áreas de ocorrência das três espécies. O NDVI se mostrou um índice eficaz no entendimento da resposta das MAE às condições hidrológicas, mesmo apresentando muita dificuldade na diferenciação de vegetação e água sob condições de cheia. De modo geral, foram encontrados bons coeficientes de determinação entre o NDVI e o IAH médio de três meses (mês da imagem + dois meses anteriores à data da imagem), e entre o NDVI e a condição hidrológica (nível d água) de dois meses anteriores à data da imagem. Esses resultados são indícios de que os efeitos das condições hidrológicas sobre as MAE estudadas não são prontamente detectados, e que ações antrópicas podem produzir efeitos a longo prazo.
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Impact of climate change on fresh water resources of Elliot town in the Eastern CapeNdlela, Bekithemba 11 1900 (has links)
Climate change and variability have great impact on the hydrological cycle and consequently on the availability of water resources. Variations in temperature and precipitation trends that are
occurring are a consequent of the increase in the concentrations of greenhouse gases, which are subsequently affecting the hydrological cycle. This in turn affects water quantity and quality, which is essential for agriculture, domestic and industrial uses. This study, done in Elliot Town and the surrounding areas of Sakhisizwe Municipality in the Eastern Cape Province of South Africa, evaluates how climate change and variability is affecting water availability and its quality in the town. The impact climate change and variability on agricultural production is also assessed. Remote Sensing, Geographic Information Systems (GIS), databases and some statistical packages have been used to collect, analyse and create spatial maps used to derive concrete conclusions. The methods used aided in spatially analysing the changes in temperature and rainfall along the years and make a comparative analysis. The study has shown that the spatial changes in the amount, intensity and frequency of rainfall affects the magnitude and frequency of stream flows; consequently, increasing the intensity of floods and droughts that have been recurring in the last few decades. The municipality is more affected by climate variability than change, and the resultant extreme climate events are affecting the water resources resulting in domestic water cuts, poor water quality and low agriculture productivity. This study recommends the importance of an awareness campaigns on climate change and variability and their effect directed towards the community, especially on novel water harvesting technologies. The study also highlights the
importance of a robust early warning system to prepare the community in case of a climate shock, which is an area that needs further research. / Environmental Sciences / M. Sc. (Environmental Science)
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Väneramplitud – Lönsamhet? : Kvalitativ studie av åtgärder, genomförda för att reducera risker och kostnadspåföljder av en förändrad vattenregim / Väner lake amplitude – Profitable?Linzie, Martin January 2013 (has links)
Tappningsstrategin för Vänern ändrades i ett beslut från Länsstyrelsen i Västra Götalands län och Vattenfall AB, på uppdrag av regeringen år 2008. Detta gjordes för att minska risken för översvämningar i Vänern. Åtgärden var föreslagen av Klimat- och sårbarhetsutredningen, som försökt utreda konsekvenser av klimatförändringar för Vänern i ett framtida förändrat klimat. I utredningen används en metod för att mäta kostnader. Metoden är en kostnads-nytto-analys (Cost-Benefit-Analysis; CBA) som användes för att utvärdera bland annat Vänern med omnejd. Enligt denna uppsats saknas det värdering för naturmiljö och sociala faktorer i denna utredning. Denna uppsats försöker kommentara detta faktum. Det behövs andra, eller möjligtvis förändrade metoder för att kunna värdera naturmiljön. Uteblivna ekologiska och biologiska värderingar, får konsekvenser för helheten. Den förminskade vattenamplituden kommer att få konsekvenser som ej blivit värderade, den grund som beslut fattas på är då inkomplett vilket leder till att besluten också får konsekvenser som kan vara mycket kostsamma för samhället. Denna uppsats efterfrågar via intervjuer samt en litteraturstudie, vilka ekologiska värden som förväntas påverkas och vilka metoder som kan användas eller bör användas för att uppnå en helhetssyn. Det saknas idag tillräckliga data för att ge en konsekvensanalys av denna åtgärd. Därför borde man i enlighet med denna uppsats avvaktat med ny vattenregim i Vänern, tills alla fakta i målet finns att tillgå. / The water amplitude of the lake Vänern was lowered by a decision by the County Administrative board of Västra Götaland, this was carried out by the electric company Vattenfall AB in the year 2008. This was done to reduce the risks of severe flooding’s. The procedure was recommended by the report “Climate and vulnerability”. This will have adverse effects on the natural values around Vänern. The method used in the report was the Cost-Benefit-Analysis (CBA) method. In this valuation method, it is very difficult to value natural values according to their monetary value since the method itself lacks the procedures to do so properly. And also the investigators chose to not value these in a monetary sense because of the difficulties in doing so. This thesis questions through interviews and an extensive literature study why this came to pass, and how and why the natural values of the lake Vänern could have been valued. The possibility that the adverse effects on the natural values around the lake is diminishing is a fact not implemented in the report makes the proceeding decision to lower the water amplitude of Vänern, makes it difficult to determine the final consequences.
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Les surcotes et les submersions marines dans la partie centrale du Golfe de Gascogne : les enseignements de la tempête Xynthia / Storm surges and coastal floods in the central part of the Bay of Biscay : lessons from the Xynthia stormBreilh, Jean-François 18 June 2014 (has links)
Les submersions marines d’origine météorologique sont des catastrophes naturelles majeures, responsables chaque année de milliers de morts et de milliards d’euros de dégâts. La partie centrale du Golfe de Gascogne est un territoire particulièrement vulnérable à cet aléa, comme nous l’a rappelé la forte submersion engendrée par la tempête Xynthia en 2010. L’objectif de ce travail est d’améliorer la compréhension des surcotes et des submersions marines dans cette zone de France dans une approche pluridisciplinaire mêlant la géomorphologie, l’océanographie et l’analyse d’archives historiques. Afin de juger du caractère exceptionnel de Xynthia, une recherche de l’ensemble des submersions marines qui ont affecté la région d’étude depuis 500 ans a été menée. La modélisation numérique des surcotes des 5 tempêtes engendrant des submersions au 20ème siècle, révélées par ces recherches, montre que des conditions météo-marines variées ont induit des niveaux d’eau et des submersions comparables à ceux provoqués par Xynthia. Ce constat est en désaccord avec les estimations de périodes de retour de niveau marin extrêmes basées sur l’analyse statistique de mesures marégraphiques et met en avant l’apport de l’approche historique dans de telles problématiques. Devant la forte vulnérabilité des Pertuis Charentais aux submersions marines, la modélisation statique de la submersion marine, méthode simple mais néanmoins fréquemment utilisée pour estimer l’extension des zones inondées, a été évaluée. Cette méthode fournit de bonnes estimations de l’extension de l’inondation dans les zones de faibles altitudes caractérisées par une faible distance entre le trait de côte et la limite continentale de la zone inondable, mais mauvaises lorsque cette distance est grande. En effet, lorsque l’inondation se propage loin du trait de côte, la dynamique de l’écoulement ne peut plus être négligée sur ces grandes distances. Afin d’anticiper de futures submersions, deux configurations des digues ont été testées par modélisation numérique au travers de l’exemple de l’estuaire de la Charente. Les hauteurs d’eau et l’inondation de Xynthia sont simulées en augmentant la hauteur des digues de l’estuaire, empêchant toute inondation des zones basses adjacentes ; puis en abaissant les digues bordant l’estuaire au niveau des plus hautes marées astronomiques et en créant une seconde rangée de digues protégeant les zones habitées. Cette seconde configuration permet l’inondation des zones non habitées mais empêche l’inondation des zones à enjeux importants, comme la ville de Rochefort. Il est montré que la rehausse de l’ensemble des digues entraîne des niveaux d’eau supérieurs de 1.2 m à Rochefort par rapport à la simulation sans modification de digues, alors que l’abaissement de celles-ci et la protection des zones à forts enjeux ne modifient pas la hauteur d’eau dans l’estuaire. Ainsi, la rehausse des digues côtières n’est pas une solution systématique car la protection contre l’inondation de toutes les zones côtières peut augmenter la vulnérabilité des zones à forts enjeux. / Storm-induced coastal flooding are major natural disasters, responsible for thousands of deaths and billions of euros of damages each year. The central part of the Bay of Biscay is vulnerable to this hazard, as recently shown by the strong flooding induced by Xynthia in 2010. This study aims to improve the understanding of storm surges and coastal floods in this area of France, using several methods such as numerical or static modeling. To assess the uniqueness of Xynthia, historical researches of coastal floods affecting the study area for 500 years was conducted. Numerical modeling of the storm surges related to 5 storms of the 20th century revealed by these researches shows that various meteo-oceanic settings induced water levels and coastal floods comparable to those caused by Xynthia. This finding challenges return periods estimations of extreme sea levels based on statistical analysis of tide gauges measurements and highlights the contribution of the historical approach to such issues. Given the high vulnerability on coastal floods of Pertuis Charentais, static modeling, a simple but frequently used method to estimate the extension of flooded areas is evaluated. This analysis shows that this method provides good estimations of flood extents in low-lying areas characterized by a small distance between the shoreline and the continental limits of the lower area, but bad estimations when this distance is large. These poor performances when floods spread away from the coastline are explained by the dynamics of the flow, which can no longer be ignored. Two coastal defenses strategies are investigated in the Charente-river Estuary by numerical modeling. Water levels and coastal floods induced by Xynthia are simulated with increased dikes height, preventing flooding of adjacent low-lying areas, and then with dikes lowered to highest high spring tide height and with a second rank of dikes preventing flooding of important issues areas, such as the town of Rochefort. It is shown that raising dikes leads to higher levels of 1.2 m in Rochefort compared to the simulation without changing dikes, while protecting issues do not affect the water level in the estuary. Thus, it is demonstrated that the systematic raising of dikes is not a solution because it can increase the vulnerability of important issues areas.
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Stabilizace břehů nádrží / Bank Stabilization of damMartinát, Lukáš January 2012 (has links)
The aim of this project is design front breakwaters on the valley dam Brno, area Osada. These precautionaries must obviate another destruction of soil on coast, abrasion. The correct design is depending on a definition of abrasion terminant AT, it is point where regress of bank stops. We need elaborate counts of water levels in the dam for last ten years, for the definition of that abrasion point. After that follows definition of the most-count water level Mnmax and definition of a ground elevation bottom of the most highly abrasion crib Va.
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Responses of Bambara groundnut (Vigna Subterannea L. Verdc) landraces to field and controlled environment conditions of water stress.Zondi, Lungelwa Zandile. January 2012 (has links)
Bambara groundnut (Vigna subterranea L. Verdc) is a drought tolerant African legume
capable of producing reasonable yields where other crops may fail. However, it remains an
underutilised crop, owing to limited research, cultivated using landraces, of which scant
information is available describing their agronomy and genetic diversity. The aim of this
study was to evaluate the response of bambara landraces from different geographical
locations to water stress under controlled and field conditions. Seeds were sourced from
subsistence farmers of Tugela Ferry and Deepdale in KwaZulu-Natal (South Africa) and
Zimbabwe, and characterised into three seed coat colours: light-brown, brown and red.
Seed quality was assessed using the standard germination test. Vigour indices of
germination velocity index and mean germination time were determined. Seedling
establishment was evaluated using seedling trays using a factorial experiment, with four
factors: 1. provenance – (Tugela Ferry and Deepdale), 2. seed colour – (red, light-brown
and brown), 3. water regimes – (30%, 60% and 100% field capacity), and 4. soil media –
(clay, sand and clay + sand). Seedling leaf samples were used to evaluate proline
accumulation as an indicator of stress tolerance. A field trial was used to evaluate
productivity of bambara landraces under rainfed and irrigated conditions. A pot trial was
conducted under controlled environment conditions with three factors: temperature
(33/27°C and 21/15°C), water regimes (30% and 100% of crop water requirement) and
bambara landrace selections. Results showed no significant differences in germination
capacity between bambara landrace selections. Germination time differed significantly
(P<0.001) between bambara landrace selections. The Jozini provenance was shown to
perform best, followed by Zimbabwe, Tugela Ferry and Deepdale. Brown landrace
selections had higher (P<0.001) germination compared with red and light-brown
selections, respectively. Seedling establishment showed that emergence was higher
(P<0.001) at 100% FC compared with 60% FC and 30% FC. Emergence was higher (P<0.001) in the Sand+Clay mixture compared with Clay and Sand media. Dark-coloured
selections had higher (P<0.001) emergence compared with light-coloured selections.
Results from the field trial showed that the red landrace selections emerged better
(P<0.001) than the light-brown and brown landrace selections, respectively. Plant growth
was lower under irrigated compared with rainfed conditions. Stomatal conductance was
higher (P<0.001) under irrigated compared with rainfed conditions, whereas chlorophyll
content index was higher (P<0.05) under rainfed compared with irrigated conditions.
Results of the pot trial showed that emergence was significantly (P<0.001) affected by
temperature. It was higher at 33/27°C compared with 21/15°C (P<0.001). Dark-coloured
landraces had higher emergence compared with the light-brown landraces. Stomatal
conductance was lower at 30% ET relative to 100% ETc. There were no significant
differences between water regimes with respect to biomass, pod number per plant, pod
mass per plant, seed number per pod, seed mass per plant and harvest index. It is
concluded that seed colour is an important variable in the identity of bambara landraces.
Provenance plays a significant role in seed performance and there is a significant
interaction between provenance and seed coat colour. This study could be expanded to
obtain more data for crop improvement through inclusion of many sites and seasons for
better agronomic advice to farmers. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
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Will we need to change the rules : assessing the implications of climate change for dam operations in Oregon's McKenzie River BasinDanner, Allison G. 21 March 2013 (has links)
Dams and reservoirs are important components of water resource management systems, but their operational sensitivity to streamflow variability may make them vulnerable to climate change. Climate change is likely to affect the magnitude and timing of streamflow, motivating the assessment of potential impacts on dams and reservoirs. Here I examine a case study of Cougar Dam, a multipurpose dam in Oregon, USA, to assess potential impacts of future climate change on operational performance. In the first portion of this study, I examine the historical operation of Cougar Dam, to understand (1), whether operational objectives have been achievable in the past despite operational variability, and (2) how climatic variation is expressed in operational trajectories. By analyzing historical streamflow and operations data using a set of metrics, I characterize variability in past operations and how that variability relates to streamflow. I also employ a reservoir model to distinguish operational differences due to streamflow variability from variability due to other factors that affect operations. I find that operational objectives have been achievable, despite variability in operations and departures from the ideal operational trajectory. Throughout the historical period, flood control operations have almost always kept reservoir outflows below the desired maximum outflow. Although filling occurs 9 days late on average, the reservoir has filled in all but 6 out of 37 years. Although drawdown occurs 47 days early on average, early drawdown does not generally impact recreation and allows minimum outflows to be met every day during all but the driest year. I also find that total seasonal inflow is correlated with measures of operational performance, and that other factors besides climate play an important role in determining operational trajectories. I conclude that operations of Cougar Reservoir are vulnerable to climate change, but that operational flexibility may mitigate some of the potential impacts.
In the second portion of this study I assume that current operating rules will be kept in place and I aim to understand what types of operational impacts may be expected, when they may be expected to occur, and whether the operational impacts may necessitate changing operational rules. I employ both a traditional climate impacts assessment approach to assess changes over time as well as a scenario-neutral approach to generalize relationships between streamflow and operations of Cougar Dam. I find that projected increases in winter streamflow could result in up to twice the number of downstream high flows than in the past and that projected decreases in summer streamflow could result in earlier reservoir drawdown by up to 20 days on average. Additionally, filling of the reservoir may occur up to 16% more often or 11% less often than in the past, depending on spring flow magnitude and timing. I also find that there are strong general relationships between total inflow volume and flood control performance, and that there are total inflow thresholds for whether or not the reservoir will fill or will be full enough for recreation in late summer. I conclude that future modification of operating policies may be warranted, but that there will likely be tradeoffs between operating objectives in the future even if operating rules are modified. / Graduation date: 2013
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