Inventory and Distribution of Benthic Macroinvertebrates, Indicators of Water Quality in Four Forested Watercourses in Centre Region of Cameroon

The inventory of benthic macroinvertebrate species was carried out in some streams of the Mefou catchment area, from August 2021 to August 2022, in order to determine the biological groups that make up the population and characterise these environments. The dataset acquired during this study made it possible to update the existing database and contribute to the knowledge of the biological groups associated in these environments, and to provide additional information on the existing ones in relation to bioindication. Overall 80 families were identified and, on the basis of frequencies of occurrence greater than 75%, 22 families were retained as potential biological indicators. The remarkable diversity of insects and the low abundance of Diptera reflect the low degradation of environments and the good quality of water. The high diversity indices obtained reflect the maintenance of the favourable ecological conditions that favours the development of a balanced and, integrated biological community capable of adapting to changes.

Quantifying and Simplifying the 1997 UNWC’s Guidelines to Mitigate Hegemony in Transboundary Watercourse Negotiations

The 1997 United Nations Convention on the Law of the Non-navigational Uses of International Watercourses (UNWC) contains a negotiation framework for transboundary water rights. However, it is a subjective document open to a wide range of possibilities and interpretations. Water Rights Allocations (WRAs) as described by Dinar and Nigatu (2013) and Dinar and Tsur (2017) provide a limited number of quantifiable allocation possibilities based on the UNWC. It is suggested that this methodology streamlines the negotiation process and reduces the effects of hydro hegemony. These methodologies are explored and applied through a case study on the Orontes River Basin.

On the Need for Including Groundwater Allocation in Future Negotiations on the Orontes

A series of treaties between Lebanon and Syria on the use of the Orontes (‘Assi) River’s flows emerged in the mid-1990s, being reformed twice to result in a finalized 2002 agreement allocating Lebanon 96 million cubic meters (MCM) out of 403 MCM as measured at the Hermel Bridge gauge. Focusing on the area south of Ar-Rastan, Syria, this article seeks to explore these treaties’ treatment of groundwater, ultimately demonstrating that it is not sufficiently accounted for. This allows for intensive groundwater abstractions—which may be beyond the aquifer’s recharge rate—to be undertaken in Syria. The paper concludes with recommendations to better manage the basin’s groundwater resources, which include improving groundwater data, using these data to calibrate improved hydrologic models, and a renegotiation of the treaty to better account for groundwater use.

Efficacy of Watercourse Lining in Sindh —A Review Study in Relation with Kohistan Region

The total number of watercourses in Pakistan is about 110,000 and particularly in Sindh it is about 46,699, out of which 7576 have been lined from 1977 to 1998 and from 2004 to 2015;22,479 have been lined and the remaining 16,644 still require improvement. At the current rate of progress, the lining of remaining watercourses would further take about 21 years. As designed life of the improved watercourse is about 25 years. By the time of ending of many watercourse improvement programs, there will again require the rehabilitation on many of the earlier watercourse lining schemes. Generally two types of watercourse lining are practiced in Sindh i.e. Rectangular Lined Watercourses (with single and double brick walls) and Trapezoidal Concrete Lined Watercourses. Because of efficient, effectiveness, easy maintenance and repair work, the Rectangular Lined Watercourse is more frequently practiced in Sindh. It is now suggested that: to renovate the watercourses an accelerated program should be started and the system (with the sense of terms and conditions) for renovation of watercourses program should also be changed. The research work towards different types of lining materials for watercourse should be conducted. Looking to the brief review it is suggested that a fiber glass type plastic material with semi-circular or U-shaped, pre-cast fabricated RCC Trapezoidal or Parabolic in place of brick mortar and concrete could be used for watercourse lining. This methodology, proposed to be used, will enable us to determine cost-benefit ratio, life span and such other parameters for its feasibility under variable climatic conditions of Sindh (North Sindh being dry and hot, while South Sindh semi-humid and warm).

Application of Diffusion Hydrodynamic Model for Overland Flows

Modeling two-dimensional overland flow across complex real-world topography is a challenging problem. Predicting the overland flow variables for various whatif rainfall scenarios can facilitate designing water infrastructure components aimed at preventing inundation and urban flooding. Numerical models that are being used range from those that solve the simplified St. Venant equations to CFD models that solve the complete three dimensional Navier-Stokes equations. In this work, the performance of the USGS Diffusion Hydrodynamic Model (DHM) for a series of overland flow test problems was tested by comparing numerical solutions obtained for an event-driven simulation across various sensitive parameter combinations. The reliability of the model and its ability to incorporate various topographical characteristics in the domain are illustrated.