Bambara groundnut is a protein-rich legume, with food security potential in drought-prone regions. It has been grown for many centuries and has remained an important crop to most African subsistence farmers. However, despite its high nutritional status and yield advantages in poor soils, it remains one of the neglected crops by science. There have now been recent efforts to study underutilised crops, with the aim of promoting them as healthy alternatives for people facing resource and environmental challenges and to contribute to food security. In order to do this, there needs to be information that can be used to advise farmers on the agronomic aspects of producing the crop. The overall aim of the study was to evaluate the response of bambara groundnut landraces to drought under controlled environment and field conditions. Seeds were initially collected from subsistence farmers in Jozini, KwaZulu-Natal, and characterised into three seed lots distinguished by seed coat colour: red, white and brown. In the initial study (Chapter 2) seed quality of bambara groundnuts was evaluated. Seed lots were used for standard germination (SG) and cold test (CT). Seeds were germinated under two conditions, 25°C for 8 days (SG) and 4°C for 7 days followed by 8 days at 25°C (CT). Germination percentage, seedling size and mass were determined. Desiccation tolerance was evaluated by suspending 30 seeds of each seed lot over saturated salt solutions of NaCl, LiCl, KNO3 and H2O (control) for 0, 2, 4, 8, 24 and 48 hours. Five seeds were sampled at each interval and stored at -21°C for 7 days. Samples were ground and analysed for proline content. In addition, early establishment performance of bambara groundnut was evaluated under controlled environment conditions in seedling trays using two water regimes (Chapter 2). The experimental design had three factors: seed lot (colour), priming (NaCl, LiCl, KNO3, H2O and control) and water regimes [25% and 75% Field Capacity (F.C.)]. The experiment was replicated three times. Seedling emergence was determined daily for 21 days. Seedling height and leaf number were determined weekly for three weeks, thereafter, seedling leaf area, root and shoot mass (fresh and dry), root and shoot lengths and root to shoot ratio were also determined. Seedlings were later transplanted in 90 pots for a pot trial in order to evaluate growth responses of bambara groundnut to water stress; plant height, leaf number and yield components were determined (Chapter 3). Lastly, the use of planting date selection as a management strategy for managing the occurrence of water stress under field conditions was evaluated in field trials. The experimental design was a split-split-plot design with planting date as main factor (early, optimum and late), irrigation and rainfed as sub-main factor, and seed colour as sub-plots (brown, red and white) arranged in a randomised complete block design (RCBD), with three replications. There were three planting dates: 7 September (early planting), 24 November (optimum planting) and 19 January (late planting). Results from Chapter 2 showed that the brown seed lot had the highest germination across treatments, followed by red and white seeds, respectively. There were significant differences between seed lots (P < 0.05) and salt solutions (P < 0.05) with respect to proline content. Seed proline content increased from 0 to 8 hours and later declined; NaCl was associated with the highest proline accumulation. There were highly significant differences (P < 0.001) between seed colours, priming treatments and F.C., as well as their interaction, with respect to seedling emergence. White seeds had the highest emergence, followed by brown and red, respectively. Priming seeds improved their emergence compared to the control, with highest emergence being observed in seeds treated with LiCl. Priming also improved emergence under water stress; 25% F.C. had the highest emergence compared to 75% F.C. Results from Chapter 3 showed that, seeds primed with NaCl and KNO3 resulted in tallest plants with the highest number of leaves per plant. However, NaCl and KNO3 were also the most affected under water stress. Priming was shown to improve germination and early crop establishment of bambara groundnut landraces under water stress. However, yield per plant did not improve in response to either halo- or hydro-priming. Results from field trials showed that in terms of the measured plant growth parameters (plant height, leaf number and LAI), bambara groundnut landraces were sensitive water stress. Water stress decreased yield components, and hence yield. However, selection of planting dates was shown to be a useful management tool for managing water stress under water limited field conditions. Choice of planting date significantly affected both plant growth and yield. The optimum planting date resulted in the best crop growth for all measured plant growth parameters followed by late and early planting dates, respectively. Seed quality was shown to be associated with seed lot colour. Darker coloured (red and brown) seeds performed better than light (white) seeds with respect to germination. Priming was also shown to improve germination and early crop establishment of bambara groundnut landraces under water stress. However, yield per plant did not improve following priming. Growth of bambara groundnut landraces was shown to be sensitive to water stress. Water stress decreased yield components and hence yield under both controlled and field conditions. Choice of planting date significantly affected both plant growth and yield. The optimum planting date was shown to be the best performing planting date. The findings of this study suggest that bambara groundnut seed performance in terms of germination, stand establishment and productivity is associated with seed lot colour. Seed priming improves seed performance and enhances crop capacity to withstand water stress. If the optimum planting date for groundnuts (late spring to early summer) is missed, better crop performance and yield are obtained from late planting (late summer to early spring) compared with early planting (early spring). Bambara groundnut has a potential for production under water stress conditions in controlled and field environments. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

The broad objective of the study was to determine the effects of restricted water intake on the growth, blood chemistry and meat quality characteristics of indigenous chickens in semi arid environments. A total of 15 flocks in communal villages and 12 flocks in resettlement schemes of Msinga District in South Africa were monitored for 30 months to determine the effects of production system and season on flock size, dynamics and constraints faced by indigenous chicken producers. As a follow up, 281 and 233 chicks hatched in November 2011 from 18 and 9 households in communal villages and resettlement schemes, respectively were monitored using a structured checklist to determine survival and causes of mortality from hatching up to 12 weeks of age. Kaplan-Meier survival distributions and the odds ratios for effects of potential risk factors were determined using survival analysis and logistic regression models, respectively. Flock composition and structure were significantly affected by production system and month. Farmers in resettlement schemes had approximately one cock and three hens more (P < 0.05) than those in communal villages. The number of growers and chicks were similar (P > 0.05) between the two production systems but chicks were the predominant age group (38 %) of each flock. The cock to hen ratio in households in communal villages was 1:3.5, while that in resettlement schemes was 1:3.7, suggesting that inbreeding might have been reducing flock productivity. Flock sizes in communal villages peaked in March (45.1 ± 3.02) during the post rainy season and declined steadily to a low of 34.7 ± 3.63 in September during the hot-dry season. The largest flock sizes in resettlement schemes were observed in January (52.4 ± 5.09) during the hot-wet season and the smallest in August (36.1 ± 5.98) during the cold- dry season. Households in communal villages had more chicks (P < 0.05) than cocks, hens and growers throughout the year except in June when the number of growers was equal to that of chicks. In resettlement schemes, the number of chicks was lower (P < 0.05) than the number of hens and growers, except in June and July when it was equal to that of growers. Total entries were not affected (P > 0.05) by production system. Hatched chicks were the major mode of entry, accounting for more than 97 % of entries into flocks. The contribution of purchases, gifts and exchanges was negligible. Mortality was the main cause of exits from flocks, accounting for 70 and 63 % of total exits among households in communal villages and resettlement schemes, respectively. The major causes of mortality were aerial predators, sub-optimalnutrition and inclement weather conditions, which were similar between production systems. The number of birds that exited flocks through slaughter for household consumption was higher (P < 0.05) among households in resettlement (34% of total exits) than communal villages (21 % of total exits). The proportion of chickens exiting flocks through sales was higher in communal (9 %) than resettlement (4.3 %) households. Chick survival from hatching to 12 weeks was higher (P < 0.05) in communal villages (55 ± 3.14 %) than in resettlement schemes (41 ± 4.19 %). Mean chick survival time did not differ (P > 0.05) between communal (56 ± 3.30 days) and resettlement (49 ± 3.23 days) flocks. Provision of water ad libitum and treatment of sick birds were important covariates in prolonging the survival time of chicks. The effects of restricted water intake on growth performance, blood chemistry, physicochemical properties, and sensory characteristics of meat from Naked Neck (NNK) and Ovambo (OVB) chickens were also assessed. In the experiment, 54 pullets of each strain with an average weight of 641± 10g per bird were randomly assigned to three water restriction levels for 60 days in a completely randomized design. The treatments were ad libitum, 70% of ad libitum and 40% of ad libitum water intake. Each treatment group was replicated three times. The pectoralis (breast) muscle was sampled for meat quality, fatty acid composition and sensory quality analyses. Ovambo chickens had superior body-weight at 16 weeks of age, average daily gains (ADG) and average daily water intake (ADWI) than NNK chickens. Body weight of birds at 16 weeks of age, ADG, average daily feed intake (ADFI), ADWI and water to feed ratio (WFR) declined progressively (P < 0.05) with increasing severity of water restriction, while food conversion ratio (FCR) values increased (P < 0.05) as the severity of water restriction increased. Naked Neck chickens had better FCR at the 40 % of ad libitum water intake level than OVB chickens. The dressing percentage per bird was higher (P<0.05) in water-restricted birds than those on ad libitum water consumption, irrespective of strain. Heart weight was significantly lower in birds on 40% of ad libitum water intake than those on ad libitum and 70% of ad libitum water intake, respectively. Packed cell volume was higher (P < 0.05) in NNK than OVB chickens offered waterad libitum, but similar in birds offered 70 and 40 % of ad libitum. There were no differences in erythrocyte count (RBC) and mean corpuscular volume (MCV) values between strains, but MCV was higher in birds on 40 than 70 % of ad libitum water intake, irrespective of strain. Naked neck chickens had higher (P < 0.05) white blood cell count (WBC) values than OVB chickens at 40 % restriction level, but lower WBC than OVB at 70 % water restriction level. Uric acid, creatinine, triacylglycerides, total cholesterol, low density lipid cholesterol, total protein and globulin increased (P < 0.05) with each increment in water restriction, but the increase in creatinine and total cholesterol was more pronounced in OVB than NNK chickens. The opposite was observed for uric acid. Alanine transaminase, alkaline phosphatase and aspartate transaminase activities were not influenced by strain and water restriction. It was concluded that the two strains could withstand up to 40 % of ad libitum water restriction, but NNK chickens tolerated water stress better than OVB chickens. Water intake levels of 40% of ad libitum produced meat with significantly lower (P < 0.05) cooking loss, and higher (P < 0.05) redness (a*) values in NNK chickens compared with OVB chickens. Water intake level had no effect (P > 0.05) on lightness (L*) and yellowness (b*) values, shear force, moisture and protein contents in both strains. The fat content of NNK meat was 41 % lower (P < 0.05) than that of OVB meat at 70 % of ad libitum, but 31 % higher at 40 % of ad libitum water intake. The ash content was significantly elevated (P < 0.05) in birds on 70 % of ad libitum compared to those on ad libitum and 40 % of ad libitum water intake, which had similar (P > 0.05) ash contents. Birds on 40 % of ad libitum water intake had significantly higher (P < 0.05) proportions of octadecanoic acid (C18:0), cis, cis-9,12-octadecadienoic acid (C18:2 ῳ-6), cis-8,11,14,17-eicosatetraenoic acid (C20:4 ῳ-6), cis-7,10,13,16-docosatetraenoic acid (C22:4 ῳ-6), cis-4,7,10,13,16,19-docosahexaenoic acid (C22:6 ῳ-3), total polyunsaturated fatty acid (PUFA), total omega-3 PUFA and total omega-6 PUFA proportions, but lower (P < 0.05) cis-7-hexadecenoic (C16:1c7), cis-9-octadecenoic (C18:1c9), cis-11-octadecenoic acid (C18:1c11), cis-13-docosenoic acid (C22:1c13), total monounsaturated fatty acids than those on the 70% of ad libitum and ad libitum water intake, respectively. The proportion of trans-9-octadenoic acid (C18:1t9) was higher (P < 0.05) in NNK chickens on 40 % of ad libitum water intake than OVB chickens. It was concluded that water restriction at 40 % of ad libitum water intake resulted in favourable cooking loss values and meat redness (a*) values, omega-3 and 6 PUFA proportions and a high ῳ-6/ῳ-3 ratio. The high fat content of NNK chickens at 40 % of ad libitum water intake compared to OVB chickens suggests a superior adaptation to hydric stress. Naked Neck breast meat had higher initial impression of juiciness scores than that from OVB chickens, but only in birds on ad libitum and 70 % of ad libitum water intake. Sensory scores for first bite, connective tissue and tenderness decreased with increasing severity of water restriction (P < 0.05). Aroma, flavour and atypical flavour were not affected by strain or water restriction level (P > 0.05). There were significant strain differences for sustained impression of juiciness and tenderness, with the highest scores occurring in NNK chickens (P < 0.05). Aroma had a significant influence on the flavour of breast meat (P < 0.05). Fat content was significantly correlated with initial impression of juiciness, first bite and sustained impression of juiciness of breast meat. It was concluded that water restriction up to 40 % of ad libitum had a significant and adverse impact on juiciness and first bite scores of meat. / Ph.D. University of KwaZulu-Natal, Pietermaritzburg 2013.

Bibliography: leaves 103-120. / 1 v. (various pagings) : ill. (some col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Species interactions are dependent on the water regime, which affects the relative allocation to below (sediment resource acquisition) and above ground (C acquisition) parts. At shallow and regularily exposed sites, Baumea is the superior competitor. In Hacks and Bool Lagoon, South Australia, changing distribution patterns occur in deep and permanently flooded conditions, where Baumea dies back, paving the way for Triglochin to passively take it's place. / Thesis (Ph.D.)--Dept. of Botany, University of Adelaide, 1993

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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

Ces travaux de thèse concernent la morpho-dynamique d'une plage de poche sableuse, située en environnement macrotidal. L'étude est menée sur la plage de Porsmilin, une plage de type intermédiaire avec une terrasse de basse mer. Cette étude s’appuie sur des observations in situ acquises lors de campagnes de mesures, organisées au cours de cette thèse. Le principal objectif est de caractériser le rôle de la pente, dans l'équilibre dynamique existant entre les processus hydrodynamiques et la morphologie de la plage. La dynamique des niveaux d’eau, de la propagation des ondes infragravitaires et de la turbulence sont examinés et mis en regard des variations morphologiques de la plage, en particulier de la pente locale de la plage. Les niveaux d’eau sont globalement sous-estimés par les formulations empiriques proposées dans la littérature. Des formules adaptées au site de Porsmilin sont présentées. L’impact de la brisure de pente observée le long du profil de plage sur la dynamique de la plage, est étudié. La variabilité de la position de la brisure de pente est impliquée dans les processus d’accommodation à court terme de la plage. Cela se traduit par un retrait vers le haut de plage de la brisure de pente, permettant une dissipation plus efficace de l’énergie incidente par la terrasse de basse mer. En revanche, ce retrait peut conduire, à une concentration d’énergie importante en haut de plage, lors de conditions particulièrement énergétiques, associées à un marnage important. La position de la brisure de pente pourrait être un bon indicateur de l'état de vulnérabilité de la plage face à des évènements énergétiques, ce qui constitue une information primordiale dans le contexte actuel d’érosion généralisée des littoraux sableux. / This PhD work is focused on the morphodynamic of a pocket beach, located in a macrotidal environment. The beach type is intermediate, with a low tide terrace. The study is based on in situ observations, collected during field campaigns organized during the PhD. The objective is to characterize the beach slope impact on hydrodynamics processes and beach morphology. The water levels dynamic, infragravity waves propagation and turbulence generation in the swash zone, are examined and linked to the beach slope variability.The empirical formulations proposed in the literature show large under-estimations of water levels in the site. Empirical formulations adapted to the beach are proposed.The characteristic break slope presents along the cross-shore profile of low tide terrace beaches is studied. The variability of the break slope location is relevant to explain the short term accommodation of the beach. Under incident wave energy, the location of the beach slope moves shoreward, allowing higher wave dissipation by the low tide terrace. Nevertheless, the reflective part is reduced, which leads to a vulnerable state of the upper beach under strong forcing associated with high tide. The location of the beach slope is found to be a good indicator of the beach vulnerability under a given wave forcing. It provides valuable information in the globalized beach erosion context.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / Much future computer modeling of the responses of groundwater to water development stresses may be poorly done if the errors and limitations of digital models are not fully appreciated by groundwater hydrologists. Two digital models were constructed of the Tucson basin, one with 1,890 nodes of 1/4 square mile area each and one with 509 nodes of 1 square mile each. The starting point for the digital model was the 2-dimensional, linear, parabolic, time-and space-invariant differential equation of incompressible flow through porous media. An explicit finite-difference equivalent was determined, and a set of 1,890 equations were put in implicit form and solved on a computer in less than 20 seconds at a cost of 2.00 dollars. The errors associated with the model are discussed. In deciding what new data collected in the Tucson basin would give the most improvement in the digital model, a statistical decision theory approach was utilized in which expected opportunity loss and expected worth of sample were calculated for 5 variables. The data was computed using about 110 seconds of computer time, costing about 13.00 dollars. This technique has the advantage of including basin dynamics in estimating worth of additional data by means of using the digital model to compute all values of predicted and 'true' water levels included in the loss function.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / The concept of a step -drawdown test was first introduced by Jacob, and further modifications in the technique were made by Rorabaugh. Analysis of step -drawdown test data enables the quantification of the components of drawdown due to formation or aquifer loss, and due to well losses in a pumped well. This technique has been used to test approximately 100 wells that were drilled in crystalline and basalt formations in central India. Test data have been analyzed by Rorabaugh's method and by a graphical method, and the results of a number of tests are presented and discussed. Anomalies in the test analysis often proved helpful for interpreting aquifer irregularities. In general, the well loss constant decreases with an increase in specific capacity and the aquifer loss constant decreases with increasing transmissivity. Significant reductions in specific capacity during a step test occur in wells with high well losses. An attempt is made to quantify the well losses in a consolidated rock well, and a number of practical applications of step -drawdown tests are discussed.

Sweetpotato (Ipomoea batatas, L.) is one of the important sources of carbohydrates and economic income in Mozambique. As with most of the food crops in Mozambique, it is usually produced by small-scale farmers under dryland conditions. Despite the importance of the crop, the storage root yields are still low and it is difficult to keep planting material (vines) for the next planting season. One of the major challenges to production is drought stress. Drought stress affects sweetpotato by retarding aboveground growth, reducing total root yield, percentage of dry mass, and reducing the quality of the roots as a result of the increase in damage caused by the sweetpotato weevil (Cylas formicarius). The objective of this study was to identify sweetpotato genotypes tolerant to drought particularly amongst the orange fleshed types which can be used in breeding programmes to improve the drought tolerance of genotypes grown in Mozambique. To this end, 48 genotypes were evaluated in both field and greenhouse studies conducted at Umbeluzi Research Station (26º 03’ S, 32ºC 23’ E; 12 masl) located about 30 km from Maputo city. The field trial was a three replicate, α-design with split-plots. Genotypes were the wholeplot treatment factor and irrigation levels were the sub-plot treatment factor. The three irrigation levels imposed were: nonstressed plants irrigated from planting to 120 DAP; moderately stressed, plants irrigated until 60 DAP; and severely stressed, plants irrigated until 30 DAP. In the greenhouse trial the 48 genotypes were grown in wooden boxes arranged in a two replicate, randomized complete block design. The plants were exposed to water stress from 10 DAP to the end of experiment at 60 DAP. Genotypes were significantly different for all traits, namely: survival %, vine vigour, aboveground biomass, total and commercial root yield, total fresh biomass, harvest index, β-carotene content, % dry mass, dry mass yield, incidence of sweetpotato virus disease, and incidence of weevil damage. Irrigation levels were significant for the traits: survival %, vine vigour, aboveground biomass, total and commercial root yield, total fresh biomass, harvest index, β-carotene content, % dry mass, and dry mass yield. Irrigation levels were not significant for incidence of sweetpotato virus disease and incidence of weevil damage. The genotypes x irrigation levels interaction was significant for: total and commercial root yield, and incidence of weevil damage; and not significant for: survival %, vine vigour, aboveground biomass, total fresh biomass, harvest index, β-carotene content, % dry mass composition, dry mass yield and incidence of sweetpotato virus disease. The mean dry mass yields across irrigation levels of the national breeding lines and introduced genotypes were higher than the landrace genotypes. Most of the national breeding lines had higher β-carotene content than the introduced and landrace genotypes. The landrace genotypes had relatively higher % dry mass composition compared to the national breeding lines. The stress tolerance index (STI) separated the 48 sweetpotato genotypes evaluated in the field trial into three groups: drought tolerant (high STI); moderate drought tolerant (intermediate STI); and drought sensitive (low STI). Under moderate stress, yield potential (Yp) and yield in a stress environment (Ys) were highly significant, positively correlated with Mean productivity (MP), Geometric mean productivity (GMP), Stress tolerance index (STI) and Tolerance index (TOL). Under severe stress the same correlations were reported. Under moderate and severe stress, the correlation between stress tolerance index (STI) and Stress susceptibility index (SSI) was significant and negative. In the greenhouse trial, differences between genotypes in vine length increment, vine diameter increment, leaf width increment and number of nodes vine-1 were significant (P<0.05). Vine length, vine diameter, leaf width and length increments either increased or were reduced due to water stress. Less than 10% increment in vine length (between 25 and 50 DAP) was recorded in MGCl01, Atacama, Cordner, Beauregard, and CN1448-49. Higher than 40% vine length increment was recorded in Jonathan and UNK-Malawi, Naspot, MUSG0614-24, Resisto, K566632, Tainung64, Ejumula and MUSG0623-09. Vine diameter decreased in Manhissane and MUSG0616-18. No change in leaf length in Tacna and Jonathan and in leaf width in Xihetamakote and Resisto-Nairobi was recorded. The longest petiole length at 30 DAP was recorded by Tacna and the shortest by Nhacutse4. The longest internode length was recorded in 199062.1. Similar to petiole length, Nhacuste4 reported the shortest internode length. The highest number of primary vines was recorded by MUSG0608-61 and lowest by Beauregard. Of the 48 genotypes exposed to water stress, 18 survived until the end of the greenhouse experiment at 60 DAP and were therefore considered to be drought tolerant. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, 2011.

The Little Bow River Project was implemented in 2003 and includes Alberta’s newest dam. The Project involves tripling the diversion of water from the Highwood River to the Little Bow River and subsequently storing the water in the Twin Valley Reservoir. This MSc Thesis provided part of the environmental monitoring for that Project and particularly investigated the impacts of augmented flows on the river channel and riparian vegetation along the upper reach of the Little Bow River. An initial component of the long-term study was to determine the existing associations between fluvial geomorphic characteristics and riparian plant communities. Poplar (Populus balsamifera L.), willow (Salix bebbiana Sargent and S. exigua Nutt.) and wolf-willow (Elaeagnus commutata Bernh.) communities were located along the upper section of the river, where the channel had a steeper gradient and was narrower and more sinuous. Cattail (Typha latifolia L.) and grass (grasses and sedges) communities were generally located along the lower section of the river that was shallower in gradient, wider and straighter. Plant community distribution also reflected impacts from cattle grazing. Initial channel and vegetation responses in the first two years following the increase in flow augmentation were slight and included bank slumping, sediment scour and inundation of flooded zones. The initial responses are consistent with the primary prediction of channel widening and this will probably be associated with some changes in the adjacent riparian plant communities. / xiv, 139 leaves : ill. (some col.) ; 29 cm.