Thesis (M.S.)--Oregon State University, 1989. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2004. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Cooperation Agreement No. CA 8000 -2 -9001 Work Order No. 8039 -2 -9001 / Within Saguaro National Park only Rincon Mountain District contains significant riparian areas. The geologic framework of the Tanque Verde Ridge and Rincon Valley exerts strong control on the hydrology of these riparian systems. Pantano fault constitutes a line of hydrogeologic separation between the occurrence and utilization of groundwater in the Rincon Valley and the main Tucson basin. No known, comparable fault isolates the upper Tanque Verde Creek alluvium from downstream pumping effects. However, east of the confluence with Agua Caliente Wash, the highly permeable alluvial materials are much thinner, and serve to dampen such downstream effects. Therefore, the ground water reservoirs supporting the riparian areas within Rincon Mountain District are not directly connected to the Tucson basin aquifer. In what is described herein as upper basin areas, high gradient tributary streams to Tanque Verde Creek and Rincon Creek have discontinuous bodies of shallow alluvium interspersed with bedrock channel. Alluvium has accumulated behind small faults or resistant bedrock ledges and contains shallow ground water basins that support small pockets of riparian or xeroriparian vegetation. The ground water in these small basins is sustained by seeps or springs, and by runoff from precipitation and is not likely to be connected to a regional ground water system. In what we have characterized as middle basin areas, the stream gradients are less than 25m/km. In these low gradient reaches, the alluvial floodplain sediments are continuous, though not thick, as ledges of more resistant bedrock formations appear in the stream channel. These low gradient reaches contain larger volumes of ground water than the high gradient basins and support more robust riparian vegetation. The ground water in the low gradient reaches is believed to be connected to the regional ground water system. Such a low gradient reach exists in a tributary to Tanque Verde Creek about 1.4 km east of Wentworth Road and extends about 1.6 km into the Park. A similar low gradient reach occurs along Rincon Creek in the Expansion Area, and at the mouths of Chiminea and Madrona Creeks.

A finite element numerical model is developed for the modeling of coupled surface-water flow and ground-water flow. The mathematical treatment of subsurface flows follows the confined aquifer theory or the classical Dupuit approximation for unconfined aquifers whereas surface-water flows are treated with the kinematic wave approximation for open channel flow. A detailed discussion of the standard approaches to represent the coupling term is provided. In this work, a mathematical expression similar to Ohm's law is used to simulate the interacting term between the two major hydrological components. Contrary to the standard approach, the coupling term is incorporated through a boundary flux integral that arises naturally in the weak form of the governing equations rather than through a source term. It is found that in some cases, a branch cut needs to be introduced along the internal boundary representing the stream in order to define a simply connected domain, which is an essential requirement in the derivation of the weak form of the ground-water flow equation. The fast time scale characteristic of surface-water flows and the slow time scale characteristic of ground-water flows are clearly established, leading to the definition of three dimensionless parameters, namely, a Peclet number that inherits the disparity between both time scales, a flow number that relates the pumping rate and the streamflow, and a Biot number that relates the conductance at the river-aquifer interface to the aquifer conductance. The model, implemented in the Bill Williams River Basin, reproduces the observed streamflow patterns and the ground-water flow patterns. Fairly good results are obtained using multiple time steps in the simulation process.

Thesis (MSc)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: Many authors express the value of riparian vegetation in terms of the function and number of species per unit area. Although riparian vegetation is confined to narrow bands of plants along watercourses, kloofs and gullies, it is a specialised habitat for many species. To determine the contribution of riparian vegetation to the species richness of the Jonkershoek Valley, Western Cape Province, South Africa, a checklist was compiled, by referring to past research and to the PRECIS national database for the South African flora for a list of species recorded from the area. A total of 1 743 taxa and 108 families were included in this list for the Valley. Specific characteristics were attributed to each of the 1 743 species on the basis of characters determined from the literature. Analysis of these data indicates that woody perennial shrubs with sclerophyll leaves are the representative plant type for the study area as a whole. The specialist structural description of a riparian species in the Jonkershoek Valley is: an unbranched woody perennial phanerophyte of a height between 2.0-8.0 m with microphyllous sclerophyilleaves. This group contributes 63% towards the riparian flora. Riparian habitats occupy only 2.5% of the total study area but contribute 26% of the vascular plants. The riparian communities of the Santa Monica Mountains (USA) cover 0.7% of that mountain study area and provide a habitat for 20.5% of the total vascular plants of the area. Both areas, therefore, show a similar level of diversity. This remarkable species richness of riparian zones is consistent with that found in other riparian communities i.e. Sweden and France. The study area was sampled by means of relevés arranged along 53 transects through the main stem and it's tributaries. A total number of 139 relevés were recorded which were used to identify, characterise and describe the riparian communities. Eight vegetation units, consisting of two groups, three communities, two subcommunities and one form, were described. The one group described the riparian communities while the other described a seepage community. The bigger groups exhibit environmental properties over a broader spectrum, while smaller groups exhibit characteristic environmental properties. The vegetation is found to represent a continuum rather than discreet entities. Many indicator species are encountered in the communities. Because of the characteristic canopy-understorey physiognomy of riparian vegetation, many communities are interspersed, making it difficult to delineate discreet community boundaries. The vegetation of the riparian zone of the Eerste River in the Jonkershoek Valley, is relatively pristine. Thirty-six species not native to the Valley were included in the checklist of which only four were recorded during the phytosociological study. / AFRIKAANSE OPSOMMING: Verskeie skrywers beklemtoon die kosbaarheid van rivieroewerplantegroei in terme van hul funksie en aantal spesies per oppervlakeenheid. Alhoewel rivieroewerplantegroei beperk is tot 'n noue band van plante langs waterweë, klowe en skeure, is dit 'n gespesialiseerde habitat vir baie spesies. Om die bydrae wat rivieroewerplantegroei tot die spesie-rykheid van die Jonkershoekvallei, Wes-Kaapprovinsie, Suid-Afrika te bereken, is 'n spesieslys saamgestel uit vorige studies en 'n PRECIS nasionale databasis vir die Suid-Afrikaanse flora waaruit 'n lys saamgestel is van spesies wat aangeteken is vir die area. 'n Totaal van 1 746 taxa uit 108 families is ingesluit in die plantelys. Vir elk van die 1 743 spesies, is spesifieke karakters uit die literatuur bepaal. 'n Analise hiervan dui aan dat die verteenwoordigende plant van die Jonkershoekvallei as gehele studie area 'n houtagtige, meerjarige struik met sklerofil blare is. Die spesialis strukturele beskrywing van 'n plant vir die Jonkershoekvallei is as volg: 'n onvertakte houtagtige meerjarige fanerofiet met 'n hoogte van 2.0-8.0 m met mikrofilliese sklerofil blare. Hierdie groep dra tot 63% by tot hierdie flora. Rivieroewer habitatte beslaan slegs 2.5% van die totale studie area, maar het tot 26% tot die vaatplante bygedra. Die Santa Monica Berge (VSA) se rivieroewerplantegroei bedek 0.7% van die bergagtige studie area en voorsien 'n habitat vir 20.5% van die vaatpplante. Beide gebiede toon dieselfde mate van diversiteit. Hierdie uitstaande spesiesrykheid is in lyn met wat gevind is in ander rivieroewergemeenskappe bv. in Swede en Frankryk. Die studie area is gemonster deur relevés wat uitgemerk is langs 53 transekte deur die hoofstroom en die sytakke. 'n Totaal van 139 releves is gemonster wat gebruik is om die gemeenskappe te identifiseer, karaktifiseer, en te beskryf. Agt plantegroei-eenhede, bestaande uit twee groepe, drie gemeenskappe, twee subgemeenskappe en een vorm, is beskryf. Die een groep beskryf rivieroewergemeenskappe terwyl die ander groep "n gemeenskap in die syfersone beskryf. Die groter groepe het wyer omgewingseienskappe getoon, terwyl die kleiner groepe spesifieke eienskappe toon. Dit is vasgestel dat die plantegroei eerder "n kontinuum voorstel as diskrete eenhede. Dit het tot gevolg dat dit moeilik is om die grense van gemeenskappe uit te wys. Vele indikatorspesies is aangetref. Die plantegroei van die rivieroewer van die Eersterivier in die Jonkershoeksvallei, kan beskryf word as relatief onversteurd. Ses-en-dertig spesies wat nie eie aan die Vallei is nie, is ingesluit in die spesieslys waarvan vier tydens die fito-sosiologiese studie aangeteken is.

Riparian wetlands are among the most valuable landscapes in the arid southwest. Since they are sources for water and green vegetation, they are unique compared to surrounding desert landscapes. They also offer the potential for a wide range of commodity and non-commodity based land uses. In a rapidly urbanizing setting, commodity based uses such as housing, retail, and industrial development often come into conflict with non-commodity based uses such as recreation and wildlife, water and nature preservation. The purpose of this study was to deduce public value orientations toward the rapidly urbanizing riparian landscapes of Tucson, Arizona through an assessment of residents' attitudes and perceptions regarding those landscapes. Theoretical constructs addressing the relationship between attitudes and perceptions and varying conditions of residential setting, proximity, familiarity, and human influence in the landscape were also assessed. Data were collected by mail survey and by a photo-surrogate landscape assessment technique which provided data on scenic quality and the appropriateness of various land uses. Results indicate that the strongest differences across residential settings, proximity, familiarity, and human influence occur for perceptions of existing landscape conditions. Weaker differences occur for perceptions of change and opinions on planning, management, and growth. No differences were found on land use preferences. Although perceptions differ about what currently exists in the landscape, respondents are unified in their preferences for future land use. This suggests that landscape assessments based only on perceptions of existing conditions may not accurately reflect public values for future land uses. Public value orientations were found to be associated with: (1) careful planning to control growth; (2) conservation of water resources; (3) preservation and rehabilitation of natural vegetation, wildlife habitat, open space, and other non-commodity resources, and (4) development of compatible flood control structures. Results suggest that the changes occurring in the study area are incompatible with respondents' preferences for future land uses.

Inter-Basin-Water Transfers significantly reduce flow and sediment regimes to the downstream ecosystem effecting differential channel adjustment at various locations. It is not known how macroinvertebrates adjust to flow regulation, either spatially or temporally, because research is lacking into how morphological adjustment affects benthic habitat. Feedback mechanisms that initiate the adjustment process must first be identified, then the effect on benthic habitat becomes apparent, thus, providing a link to macroinvertebrate response. Since regulation there has been a 95% reduction in flow volume, a complete downward shift in both the flow duration and flood frequency curves and a 194% increase in flow constancy compared to the pre- dam period. Furthermore, Jindabyne Dam traps 99.9% of the total incoming sediment load. Upstream of the tributary the dominant river response was accommodation adjustment with subsequent contraction of the river channel. Associated feedback mechanisms were ?armouring? and vegetation encroachment. Downstream of the tributary response was more complex, with channel contraction through aggradation and specifically the formation of a tributary mouth bar and fan, mid channel lobate bar, transverse bar and in-channel bench. Associated feedback mechanisms were interactions between vegetation and sediment; channel morphology, flow and sediment distribution; and sediment distribution, flow and channel morphology. These processes have had site specific and reach scale impacts on benthic habitat. Macroinvertebrate response to flow regulation was habitat specific (riffle or edge) and seemed to correspond to either site, or reach scale morphological adjustment, whereas, flow constancy seemed to affect edge macroinvertebrates throughout both reaches. Spatially, macroinvertebrates have not adjusted to the post- dam flow regime and temporally, macroinvertebrates have not recovered 30 years after the closure of Jindabyne Dam. How physical processes change habitats and how these impact on a river?s ecology and at what scale, are important considerations in river management.

Because riparian canopy controls most energy inputs to stream ecosystems, it directly affects the structure of aquatic food webs and the ecological processes that govern interactions among trophic levels. This study addresses the interdependence among riparian canopy, benthic community structure, and the carrying capacity of high desert streams for salmonid fishes. In streams in the lower John Day River Basin in eastern Oregon, algal, invertebrate, and fish communities were compared in reaches with varying densities of riparian canopy. Water temperatures varied with the density and upstream extent of canopy. Densely canopied sites were cool, while sites with high irradiances had temperatures exceeding the upper lethal limit for salmonids. Periphyton and grazer biomasses were greater in well-lighted sites, but 90% of grazer biomass consisted of Dicosmoecus gilvipes, a large caddisfly inedible by juvenile trout. Warmer water increased metabolic demands for salmonids, while the overwhelming dominance of Dicosmoecus in open sites shifted energy flow away from trout and shrunk their food base. High water temperatures, however, provided suitable habitat for many warmwater fishes which would otherwise not enter tributaries of this size. At higher elevation study sites in Camp Creek, light levels were higher and less variable than at the lower sites. Periphyton and invertebrate abundances were not correlated with irradiance. Rather, periphyton was maintained at low levels by grazers, particularly Dicosmoecus and snails. Manipulations of fish densities in enclosures showed that trout and dace had no negative impacts on numbers of invertebrate prey, and that grazers played a larger role in regulating lower trophic levels than did fish. Dicosmoecus acted as a keystone species in the benthic food web of Camp Creek by simultaneously influencing the trophic level both below and above its own. When irradiance was experimentally reduced under artificial canopies, periphyton standing crops were not different from those in open control pools after 4 wks. However, grazers were more abundant in open pools. The cropping of periphyton to uniform levels in both sunlight and shade indicated that mobile grazers targeted sites of varying productivities. Comparisons between benthic communities in Camp Creek and in a densely canopied reference stream suggested that benthic community structure shifted to accommodate changes in energy resources that occur when canopy density is altered. / Graduation date: 1998

Thesis (M.S.)--Washington State University, 2003. / Title from PDF title page (viewed on May 22, 2005). Includes bibliographical references (p. 52-56).

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