Dependence of discharge, channel area, and flow velocity on river stage and a refutation of Manning’s equation

ABSTRACT Field data reveal how the discharge (Q), channel area (A), and average water velocity (Vavg) of natural streams functionally depend on the effective stage (h) above channel bottom. A graphical technique allows the level that corresponds to a dry channel, denoted “h0,” to be determined, permitting the dependent variables Q, A, and Vavg to all be expressed as simple functions of h, equal to hL– h0, where hL is the local stage that is typically reported relative to an arbitrary, site-specific datum. Once h0 is known, plots of log Q, log A, and log Vavg versus log h can be constructed using available data. These plots define strong, nearly linear trends for which the slopes (1) quantify the power relationships among these variables; (2) show that Vavg varies nearly linearly with h, unlike behaviors assumed in the Chezy and Manning equations; (3) distinguish the individual contributions of A and Vavg to discharge, which is their product; (4) provide quantitative means with which to compare different sites; and (5) offer new insights into the character and dynamics of natural streams.

Using InVEST to evaluate water yield services in Shangri-La, Northwestern Yunnan, China

Water yield is an ecosystem service that is vital to not only human life, but also sustainable development of the social economy and ecosystem. This study used annual average precipitation, potential evapotranspiration, plant available water content, soil depth, biophysical parameters, Zhang parameter, and land use/land cover (LULC) as input data for the Integrated Valuation of Ecosystem Service Tradeoffs (InVEST) model to estimate the water yield of Shangri-La City from 1974 to 2015. The spatiotemporal variations and associated factors (precipitation, evapotranspiration, LULC, and topographic factors) in water yield ecosystem services were then analyzed. The result showed that: (1) The water yield of Shangri-La City decreases from north and south to the center and showed a temporal trend from 1974 to 2015 of an initial decrease followed by an increase. Areas of higher average water yield were mainly in Hutiaoxia Town, Jinjiang Town, and Shangjiang Township. (2) Areas of importance for water yield in the study area which need to be assigned priority protection were mainly concentrated in the west of Jiantang Town, in central Xiaozhongdian Town, in central Gezan Township, in northwestern Dongwang Township, and in Hutiaoxia Town. (3) Water yield was affected by precipitation, evapotranspiration, vegetation type, and topographic factors. Water yield was positively and negatively correlated with precipitation and potential evapotranspiration, respectively. The average water yield of shrubs exceeded that of meadows and forests. Terrain factors indirectly affected the ecosystem service functions of water yield by affecting precipitation and vegetation types. The model used in this study can provide references for relevant research in similar climatic conditions.

Measuring operational and quality-adjusted efficiency of Chilean water companies

The path to a sustainable management of the urban water cycle requires the assessment of both operational and quality-adjusted efficiency in a unified manner. This can be done by the use of non-radial Data Envelopment Analysis models. This study used Range Adjusted Measure models to evaluate the operational, quality-adjusted, and operational & quality-adjusted efficiency (O&QAE) scores of the Chilean water industry including water leakage and unplanned interruptions as undesirable outputs. It was found that on average water utilities presented large O&QAE scores over time. The mean O&QAE score was 0.964 which means that water utilities could further reduce costs and undesirable outputs by 3.6% on average, while trying to expand the scale of operation. This finding suggests that excellent quality-adjusted efficiency at an efficient expenditure could be feasible. It was also evidenced that customer density, mixed water resources, and ownership influenced the O&QAE of Chilean water companies.

Topography Impacts Hydrology in the Sub-Humid Ethiopian Highlands

Understanding the relationship between topography, hydrological processes, and runoff source areas is essential in engineering design, such as predicting floods and implementing effective watershed management practices. This relationship is not well defined in the highlands with a monsoon climate and needs further study. The objective of this study is to relate topographic position and hydrological response in tropical highlands. The research was conducted in the Debre Mawi watershed in the northwest sub-humid Ethiopian highlands. In the monsoon rain phase of 2017 and 2018, groundwater depth, infiltration rate, and surface runoff were monitored at the upslope, midslope, and downslope positions. Surface runoff rates were measured in farmer fields through distributed V-notch weirs as estimates of positional runoff. Average water table depths were 30 cm deep in the downslope regions and 95 cm in the upslope position. The water table depth affected the steady-state infiltration rate in the rain phase. It was high upslope (350 mm h−1), low midslope (49 mm h−1), and zero downslope. In 2017, the average runoff coefficients were 0.29 for the upslope and midslope and 0.73 downslope. Thus, topographic position affects all aspects of the watershed hydrology in the humid highlands and is critical in determining runoff response.

Climate change impact to dam Operation, case study of Darma Dam, West Java

Darma Dam is located in the upstream of Cisanggarung River, Kuningan Regency, West Java Province. Darma Dam construction dated from about 1922. Indonesian government continued the construction and began operating in 1962. With effective storage of about 40 million m3, Darma Dam provides water for about 22 thousand irrigation areas and bulk water for several cities and regencies. Several problems encountered in Darma Dam operation and water management are 1) increasing water demand from domestic and industrial sectors, and 2) high inflow variation during the dry and wet season, resulting in a large amount of water spill from the dam spillway. This paper addressed the impact of climate change on the inflow variation of Darma Dam in the dry and wet seasons. Further analysis shows average water spills from the spillway during the wet season may increase from about 12 million m3/year in the present condition to about 20 million m3/year in 2020-2050, while the average water volume during the dry season may reduce from 22.5 million m3 in the present condition to about 20.7 million m3 in 2020-2050. This study suggests that dam operation need adjustment in the future as part of adaptation to climate change.

Water demand management at rural area using Micro-Component Analysis: a case study at Kenyir Lake, Malaysia

Water is one of the cornerstones in human survival and a necessity for socio-economic development. Due to that, effective management of water demand especially in the rural area becomes vital. The objective of this study is to conduct a water demand study at Kenyir Lake, Terengganu using Micro-Component Analysis (MCA). Water demand is also being assessed using National Water Services Commissions (SPAN) Guidelines, parallel to water guidelines applied for Malaysia’s building and comparison purposes. MCA considers detailed parameters of water use activities of the respective study area, whereas SPAN Guidelines use the fixed values of average daily water demand according to the type of building. The available dataset was interpreted using MCA and SPAN Guidelines, resulting in total daily water demand at Kenyir Lake of 1249.8 m3 and 1254.1 m3 respectively. Estimated water demand using SPAN Guidelines is found to be higher than MCA. The value differences occur due to the average water demand value in the guideline that is limited to a specific type of premises and does not comply with premises there. The estimated water demand can be adopted as a baseline for water companies and the government to improve the demand and supply of water.

STRUCTURAL FEATURES OF A WATER INTAKE FACILITY FOR MOUNTAIN AND SUBMOUNTAIN RIVERS

Introduction: The rate of urbanization is currently high. Therefore, it is important to use various elements and devices for water intake and water supply. Purpose of the study: We aimed to consider and analyze the structural features of a water intake facility for mountain and submountain rivers. Methods: In the course of the study, we used the synergistic research principle and statistical analysis. We analyzed the types of water supply networks at mountain rivers and identified the features of water intakes at water sources of this type. Results: A description of water intake features under flood conditions in the Amur Region, exemplified by the Bureya River, was obtained. The mountain rivers have an uneven runoff, which fluctuates not only throughout the year but also throughout the day. The water supply of the mountain and submountain areas shapes the idea of hydrological control over the regime of the mountain rivers. This paper will help to study changes in the average water inflow over the years and thus facilitate an accurate and detailed description of the water inflow characteristics in the Bureya reservoir when planning the water-energy modes of the hydroelectric power plant.

Midterm impacts of a water drought experience: evaluation of consumption changes in São Paulo, Brazil

From late 2013 until the beginning of 2015, the metropolitan region of São Paulo, Brazil, experienced a severe water shortage. During that period, economic incentives were implemented by the regional water provider in a successful attempt to reduce water consumption. We aimed to investigate whether such incentives, as well as the experience of a scarcity period itself, had a persistent impact on consumer behaviour after the water crisis was over. This study was conducted by means of a hierarchical linear model with three levels (HLM3) to verify if the reduction effect remained in the midterm and a regression using panel data to understand which factors influenced water consumption behaviour change before, during, and after the local severe water drought. The results indicate that the average water consumption level subsequent to the rain scarcity period was significantly lower than before and that, in addition to the economic incentives, the severity of the scarcity event explained the behaviour change verified in water consumption.

Genetic Improvement of Local Red Peanut With Using Nuclear Technique (Multigamma Irradiation) for Obtaining Superior Variety

The main problem examined in this study concerns the breeding of local red peanuts (Arachis hypogaea L.) to use standard multigamma irradiation methods to obtain superior variety that can be adapted to drought conditions, pests-diseases, extreme climate, and high production. The research objective was to develop local red peanut variety to use multigamma irradiation and careful selection for obtaining superior variety that can be adapted to drought conditions, pests-diseases, extreme climate, and high production. Research methods include multigamma irradiation, observation, sampling, carefully selection, comparative, and interpretation. The results of the study are as follows: The development of local red peanut variety through breeding to use multigamma irradiation and careful selection resulted in superior variety that could adapt to drought conditions, pests-diseases, extreme climate, and increased production significantly. The range of production of selected superior variety resulting from multigamma irradiation was (3.68-4.10) t ha-1 with an average production of 3.92 t ha-1. The percentage increase in the production of selected superior variety was 49.23% with an average water content of dry seeds of 11.3%.

A conceptual geological model for offshore wind sites in palaeo ice stream settings: The Utsira Nord site, North Sea

Conceptual geological models of the shallow subsurface which integrate geological and geotechnical information are important for more strategic data acquisition and engineering at offshore wind sites. Utsira Nord is an offshore wind site in the Norwegian North Sea. It covers an area of 23 km x 43 km within the Norwegian Channel palaeo ice stream, with an average water depth of 267 m making the site a candidate for floating offshore wind. The goal of this study is to present a preliminary conceptual geological model for the site, which combines an overview of previous knowledge about the complex ice streaming history of the Norwegian Channel with key observations from high resolution bathymetric data, 2D acoustic data, and shallow cores. Despite limited data, four geotechnical provinces can be defined: 1) exposed glacimarine to marine sediments, 2) buried to exposed subglacial traction till, 3) buried lodgment till and 4) shallowly buried to exposed crystalline bedrock. The model serves as a basis for planning site surveys at Utsira Nord and as a reference for offshore wind sites on other formerly glaciated coasts where palaeo ice stream systems are common, such as the northern coastlines of the United States and the United Kingdom.