The Downstream Impacts of Ethiopia's Gibe III Dam

If Ethiopia completes the Gibe III Dam, now under construction on the Middle Omo River, and continues to press ahead with large-scale irrigation developments in the Lower Omo Basin, the result will be a cascade of hydrological, ecological and socio-economic impacts that will generate a region-wide crisis for indigenous livelihoods and biodiversity and thoroughly destabilize the Ethiopia-Kenyan borderlands around Lake Turkana. The long-term effect could parallel what has happened to Central Asia's Aral Sea, one of the planet's worst environmental disasters. This African crisis is fast becoming an issue that will increasingly engage the international community.This paper summarizes the technical and scientific evidence derived from decades of high-quality research on and around the lake by local and international specialists, as well as recent studies of current threats. It then reviews expected consequences of a variety of potential strategies that might be pursued by various actors to oppose or moderate these threats

Contributions of the seasonal and long term flood patterns of River Niger to the development and control of water hyacinth (Eichhornia crassipes) in Kainji Lake, Nigeria

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Efficacy and persistence of sustained-release methoprene pellets against Aedes mosquitoes in an irrigated pasture.

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Comparative analysis of spring flood risk reduction measures in Alaska, United States and the Sakha Republic, Russia

Thesis (Ph.D.) University of Alaska Fairbanks, 2017River ice thaw and breakup are an annual springtime phenomena in the North. Depending on regional weather patterns and river morphology, breakups can result in catastrophic floods in exposed and vulnerable communities. Breakup flood risk is especially high in rural and remote northern communities, where flood relief and recovery are complicated by unique geographical and climatological features, and limited physical and communication infrastructure. Proactive spring flood management would significantly minimize the adverse impacts of spring floods. Proactive flood management entails flood risk reduction through advances in ice jam and flood prevention, forecasting and mitigation, and community preparedness. With the goal to identify best practices in spring flood risk reduction, I conducted a comparative case study between two flood-prone communities, Galena in Alaska, United States and Edeytsy in the Sakha Republic, Russia. Within a week from each other, Galena and Edeytsy sustained major floods in May 2013. Methods included focus groups with the representatives from flood managing agencies, surveys of families impacted by the 2013 floods, observations on site, and archival review. Comparative parameters of the study included natural and human causes of spring floods, effectiveness of spring flood mitigation and preparedness strategies, and the role of interagency communication and cooperation in flood risk reduction. The analysis revealed that spring flood risk in Galena and Edeytsy results from complex interactions among a series of natural processes and human actions that generate conditions of hazard, exposure, and vulnerability. Therefore, flood risk in Galena and Edeytsy can be reduced by managing conditions of ice-jam floods, and decreasing exposure and vulnerability of the at-risk populations. Implementing the Pressure and Release model to analyze the vulnerability progression of Edeytsy and Galena points to common root causes at the two research sites, including colonial heritage, unequal distribution of resources and power, top-down governance, and limited inclusion of local communities in the decision-making process. To construct an appropriate flood risk reduction framework it is important to establish a dialogue among the diverse stakeholders on potential solutions, arriving at a range of top-down and bottom-up initiatives and in conjunction selecting the appropriate strategies. Both communities have progressed in terms of greater awareness of the hazard, reduction in vulnerabilities, and a shift to more reliance on shelter-in-place. However, in neither community have needed improvements in levee protection been completed. Dialogue between outside authorities and the community begins earlier and is more intensive for Edeytsy, perhaps accounting for Edeytsy's more favorable rating of risk management and response than Galena's

Small-scale inland fisheries in Africa: How to collect data for poverty assessment?

Accurate poverty assessments in developing countries require efforts to collect detailed household level data. Especially in Africa, such procedures are time consuming, expensive and can be subject to numerous constraints. In this paper we discuss the procedure of the collection of data on consumption, income and assets from poor households involved in small-scale inland fisheries as well as agricultural activities. A sampling scheme has been developed that captures the heterogeneity in ecological conditions and the seasonality of livelihood options. Sampling includes a three point panel survey of 300 households. The respondents belong to four different ethnic groups randomly chosen from three strata representing different ecological zones. In the first part of the paper the methodological framework, the survey design and interview procedure adapted to the conditions in Northern Cameroon is discussed. The second part of the paper presents selected results of the baseline study on consumption, income and assets for different types of households. In addition the record of past ecological, economic and social shocks is presented. --

Climatic control on the peak discharge of glacier outburst floods

Lakes impounded by natural ice dams occur in many glacier regions. Their sudden emptying along subglacial paths can unleash similar to 1 km(3) of floodwater, but predicting the peak discharge of these subglacial outburst floods ('jokulhlaups') is notoriously difficult. To study how environmental factors control jokulhlaup magnitude, we use thermo- mechanical modelling to interpret a 40- year flood record from Merzbacher Lake in the Tian Shan. We show that the mean air temperature during each flood modulates its peak discharge, by influencing both the rate of meltwater input to the lake as it drains, and the lake- water temperature. The flood devastation potential thus depends sensitively on weather, and this dependence explains how regional climatic warming drives the rising trend of peak discharges in our dataset. For other subaerial ice- dammed lakes worldwide, regional warming will also promote higher- impact jokulhlaups by raising the likelihood of warm weather during their occurrence, unless other factors reduce lake volumes at flood initiation to outweigh this effect

An Archaeological and Historical Survey of Walnut Creek, Seguin, Texas

During March 1977, the Center for Archaeological Research conducted archaeological and historical surveys of Walnut Creek at Seguin, Texas. The surveys were performed under contract with Hallenberger, Galindo and Associates, Consulting Engineers. This engineering firm, in turn, has been contracted by the U.S. Corps of Engineers to do a study of proposed flood control developments along Walnut Creek in anticipation of the projected 50-year flood cycle. The archaeological and historical surveys of Walnut Creek Were part ofa larger study to assess the environmental impact of the area by the proposed flood control developments. This report, which describes the surveys made along Walnut Creek, is presented in two parts: Part I deals with the historical survey and is written by James E. Ivey; Part II covers the archaeological survey done by Cristi Assad and Erwin Roemer. The results of these surveys and suggested recommendations are presented herein

Geomorphologic impact of outburst flood cycle in braided gravel-bed rivers: confluence of Colonia and Baker rivers, Patagonia, Chile

Colonia River, as other glacial streams influenced by global warming, is affected by Glacial Lake Outburst Floods (OF). We present a study on geomorphologic features of Colonia River to comprehend the impact of OFs in sedimentary processes, analysing erosion and deposition linked to OF phenomena and frequency (since April 2008, more than 12 OFs have occurred). Interpolation analysis is carried out to create an elevation surface (DTM) from a set of sample measurements, given by contour line (2007 LiDAR) and rtkGPS point (2011 and 2012) data. These were used to create DTMs applying Delaunay triangulation. A comparisons between morphology during the current OF cycle that started on 8 April 2008, and the previous morphology (after 40 years without OFs, since end of previous cycle in 1968), is carried out through the creation of DEMs of Difference (DoDs) based on TINs. We created two DoDs, respectively between 2011-2007 (before/after the OFs cycle) and 2012-2011 (during the cycle, after the events of January and April 2012) to provide a high-resolution, spatially distributed surface model of topographic and volumetric change through time. The floodplain has been classified on the basis of the morphological characteristics: main and secondary channel(s), bars, braided area, island and delta fan features. The changes evidenced in the DoD are segregated according to these categories plus the geomorphic change taking place in each category (using GCD; Wheaton et al 2014). Issues regarding data quantity and quality will be discussed, and implications for the planned mega-dam that would flood the confluence

Longitudinal Tidal Dispersion Coefficient Estimation and Total Suspended Solids Transport Characterization in the James River

The longitudinal dispersion coefficient is a parameter used to evaluate the effect of cross-sectional variations on substance mixing mechanisms in estuaries influenced by tide, wind and internal density variations. Considering a two dimensional approach, this study aims at evaluating a tidal area of the lower James River at approximately 19 miles upstream from the mouth at the Chesapeake Bay, in the City of Newport News, and applies an experimental procedure based on in-situ salinity concentrations to estimate the dispersion coefficient in the area where receives a discharge from the HRSD James River Wastewater Treatment Plant, and further characterizes Total Suspended Solids (TSS) mixing and transport mechanisms in the surrounding area. In-situ data collection was carried out twice a day during two consecutive days (July 21st and July 22nd, 2016) to measure salinity, turbidity, temperature and velocity. Subsequently, Control Volume (CV) approach method with Steady State Response Matrix (SSRM) was applied to characterize the transport mechanism of Total Suspended Solids among eight segments in the study area, with two of them acting as boundary conditions. Statistical General Linear Model (GLM) method was used to develop in-situ correlationship between Turbidity and Total Suspended Solids from historical HRSD James River plant data series during the years 2001 through 2015. Then measured Turbidity values were used to estimate corresponding Total Suspended Solids concentrations used in the study. The results obtained during this research suggest that in the study area of the James River, dispersive mechanisms of Flood cycles influence the transport of TSS towards the upstream, reducing the effect of advective movement from the Warwick River towards the lower reach of the James

State resource management and role of remote sensing

Remote sensing by satellite can provide valuable information to state officials when making decisions regarding resources management. Portions of California's investment for Prosperity program which seem likely candidates for remote sensing include: (1) surveying vegetation type, age, and density in forests and wildlife habitats; (2) controlling fires through chaparal management; (3) monitoring wetlands and measuring ocean biomass; (4) eliminating ground water overdraught; (5) locating crops in overdraught areas, assessing soil erosion and the areas of poorly drained soils and those affected by salt; (6) monitoring coastal lands and resources; (7) changes in landscapes for recreational purposes; (8) inventorying irrigated lands; (9) classifying ground cover; (10) monitoring farmland conversion; and (11) supplying data for a statewide computerized farmlands data base