St. Stephen Fish Lift Inlet Hydraulic Barrier Investigation: A Field Survey and Hydraulic Model Study

2010 S.C. Water Resources Conference - Science and Policy Challenges for a Sustainable Futur

Assessing the impacts of cassava technology on poverty reduction in Africa

In Africa, there have been successes in cassava research in terms of the development of production technologies, particularly improved varieties with high yield potential. The study addresses the question of whether and to what extent adoption of improved cassava varieties has led to rural poverty reduction in four African countries, namely Tanzania, Democratic Republic of Congo, Sierra Leone and Zambia. Data for the study come from a household survey conducted in the above-mentioned countries through a multinational-CGIAR support to agricultural research for development of strategic crops (SARD-SC) project in Africa. Given the observational nature of the data, a parametric approach (endogenous switching regression model) is applied. The results indicate that the model detects selectivity bias. Accounting for the bias, we find that adoption of cassava technology has resulted in an approximately 10 percentage point reduction in the poverty rate. Given an adoption rate of 34 per cent and a 10 percentage point reduction in the poverty rate, an estimated 24,309 households (equivalent to 194,469 individuals) have managed to move out of poverty in these four countries as a result of adoption of the technology. We also find that adoption of the technology has benefitted non-poor and female-headed households, relative to poor and male-headed households. The results present important evidence in favour of promoting cassava technology in a targeted fashion as part of an effective poverty reduction and sustained agricultural growth strategy in Africa. Considering the large realised and even more pronounced potential impacts of the adoption of cassava technology on poverty reduction, it is vital that regional and global development organisations should continue supporting the existing cassava improvement programme to sustain the technology development efforts in the continent

The household welfare impacts of an agricultural innovation platform in Uganda

Technical approaches to food production are important to the food security of growing populations in developing countries. However, strategic investments in research and farm-level adoption require greater coherence in agricultural, societal, and local policies. The Agricultural Innovation System (AIS) and the formation of the Cassava Innovation Platform (CIP) in Uganda were designed to stimulate interactions between researchers and farmers, leading to the development of improved cassava varieties through Participatory Plant Breeding (PPB) and Participatory Variety Selection (PVS). Moreover, the establishment of a community-based commercialized seed system allied Cassava Seed Entrepreneurship (CSE) has made an important contribution to the rapid multiplication and dissemination of clean planting materials in Uganda. The impact of CIP participation on rural household welfare was measured by household consumption expenditure per capita. The Endogenous Switching Regression (ESR) model was applied to data from a formal household survey conducted in the Eastern, Northern, and Mid-Western regions of Uganda. The education, farm size, livestock size, access to credit, cost of cassava planting materials, access to extension service, access to training, and social group membership are significantly associated with CIP participation. CIP participation resulted in a 47.4% increase in household consumption expenditure. This important evidence highlights the need to promote agricultural innovation platform for improving rural livelihoods. Moreover, CIP participation has impact heterogeneity within the participant group that is conditional on household characteristics such as the gender of the household head, pointing to the need to tailor specific interventions and target specific groups within farm households

A diagenetic two-layer eutrophication model for Tolo Harbour, Hong Kong

published_or_final_versionCivil EngineeringDoctoralDoctor of Philosoph

Hydrodynamic design in coastal wetland restoration

Coastal wetlands in California are critically positioned at the interface between increasingly developed watersheds and the coastal ocean. These wetlands provide habitat for fish and wildlife, provide nutrients to surrounding coastal waters, and create recreational opportunities (Mitsch and Gosselink 1986). This report describes a circulation and transport model that is designed for tidal wetland circulation and mixing studies. Given the importance of wetland restoration projects to offset the impact of coastal development, wetland circulation and mixing models are of great utility for evaluating the advantages and disadvantages of various wetland restoration alternatives relative to issues such as bathing water quality, eutrophication, and sedimentation. An application of the model to a restored wetland and guidelines for its use are presented

Supercritical stormwater flow interception through bottom rack with transverse barrier

The Hong Kong West Drainage Tunnel (HKWDT) system consists of 34 stormwater intake structures designed to intercept stormwater runoff in upland catchments. During stormwater events, each of these intake structures intercepts and diverts the upstream supercritical flow into a bottom rack chamber connected to a supercritical vortex drop. Small surface flows are conveyed to the downstream drainage system through a narrow low-flow channel (LFC) along one side of the intake. The LFC is designed for a capacity of 20  L/s. However, when the intakes are in operation, observations suggest that the stormwater flows conveyed via the LFC might be significantly more than the design values. We report an investigative physical and numerical modeling study of the hydraulic performance of a representative existing intake structure. A 1:12 undistorted physical model based on Froude similitude was designed to study the complex hydraulic interaction of the incoming supercritical flow with the transverse barrier, bottom racks on top of the rack chamber, and a low-flow channel in supercritical flow regime. The interception capacity and flow characteristics of the bottom rack intake is predicted via a two-dimensional (2D) numerical solution of the shallow water equations using a shock-capturing finite-volume method. Physical model tests and numerical experiments were carried out for representative design flow events including those for storms with 2-, 10-, 50-, and 200-year return periods with climate change. The predicted flow features—including the discharge intercepted by the bottom rack chamber and the low-flow channel—were compared with experimental observations. The results indicate that the unintercepted flow in typical rainstorm event was 0.5  L/s in the physical model, corresponding to 0.25  m3/s in field conditions. Under a 200-year rainstorm with climate change, the unintercepted flow was 2.3  L/s in the physical model, corresponding to 1.15  m3/s in field conditions. Overall the model results show that around 10% of the inflow enters the LFC at high inflows—around 2  L/s or 1  m3/s of prototype flow—which is much higher than the 20-L/s design target; this confirms the observation that the stormwater runoff conveyed to the downstream drainage system is more than originally designed. Finally, through a combination of heuristic reasoning and physical model studies, the existing intake structure design was modified to improve interception performance. The improved interception was verified through hydraulic model simulation. Furthermore, the applicability of spatially varying rack discharge coefficient for supercritical flow above bottom racks in a 2D high-resolution hydraulic numerical model was validated

Schistosoma mansoni and other helminthes infections at Haike primary school children, North-East, Ethiopia: a cross-sectional study

Abstract Objectives Schistosomiasis and soil-transmitted helminthes infections are among the widely distributed infections worldwide. In Ethiopia, parasitic helminthic infections and schistosomiasis are among the most predominant causes of outpatient morbidity. Hence there is still lack of epidemiological information in North-Eastern Ethiopia, this study aimed to determine the prevalence and associated factors of Schistosoma mansoni and other helminthes infections at Haike primary school children, Haike, North-East Ethiopia. Results The overall prevalence of S. mansoni and other helminthes infections using formol-ether concentration technique was 85/279 (30.5%). Schistosoma mansoni was the dominant parasites as detected by both direct wet mount and formol-ether concentration technique with 44/52 (84.6%) and 65/85 (76.5%) respectively. Chi square test showed significant association between parasitic infections and age of the school children (p = 0.003). The binary logistic regression analysis was showed strong statistical association (p = 0.00) between swimming habit and parasitic infections (AOR = 6.61, 95% CI 3.31–13.12). Family used lake as source of water showed statistically significant association (AOR = 5.35, 95% CI 2.97–12.32). Furthermore, those who get water from river (AOR = 1.24, 95% CI 0.33–4.66) were more likely to be infected with S. mansoni and geo-helminthes than those who used tap water

Intention to comply with solid waste management practices among households in Butajira town, Southern Ethiopia using the theory of planned behavior.

BackgroundOne of the world's most serious environmental issues is solid waste management. It is critical for researchers to understand the intention to comply with solid waste management. Thus, we aim to determine the intention to comply with solid waste management practice among households in Butajira Town using the Theory of Planned Behavior.MethodA community-based cross-sectional study was conducted on a sample of 422 households in Butajira from June 1 to June 30, 2020. The constructs and principles of the theory of planned behavior (TPB) were measured. We selected using a systematic sampling method and collected data by using a structured interviewer-administered questionnaire. Data was analyzed using SPSS version 25.0. The predictors of intention to practice solid waste management were identified using a multivariable linear regression model. A P-value of less than 5% was considered to declare a significant association.ResultsThe findings demonstrated that intention to practice solid waste management explained 86% of the variance explained by all predictors. The perceived behavioral control construct had the greatest impact on households' behavioral intentions to comply with solid waste management practice (β = 0.16; CI (0.14, 0.18), followed by attitude (β = 0.15; CI (0.11, 0.21) and subjective norms (β = 0.12; CI (0.06, 0.17).ConclusionOur study also found that intention has a substantial influence on the behavior of solid waste management practices. Therefore, there is a need to enhance service utilization for solid waste management and to improve outdoor solid waste dropping behavior through door-to-door collection services by municipality. Furthermore, further longitudinal research should be done through intervention mapping