River Flow System Research Articles

Global Existence and Stability of Solutions to River Flow System

Global Existence and Stability of Solutions to River Flow System

PENANGGULANGAN BENCANA BANJIR DI SUNGAI BATANG MERAO PADA BADAN PENANGGULANGAN BENCANA DAERAH KOTA SUNGAI PENUH

Analysis of Flood Disaster Management in Batang Merao River at Sungai Penuh Regional Disaster Management Agency. Flooding is an event where land which is usually dry (not swampy areas) becomes inundated by water, this is caused by high rainfall and topographic conditions in the form of lowlands to sunken areas. In addition, the occurrence of flooding can also be caused by runoff which overflows and its volume exceeds the drainage capacity of the drainage system or river flow system. The occurrence of flood disasters is also caused by the low ability of soil infiltration, so that the soil is no longer able to absorb water. Flooding can occur due to rising water levels due to rainfall above normal, changes in temperature, embankments / dams that break, fast melting snow, obstructed water flow in other places. The purpose of this research is to find out how the Flood Disaster Management in Batang Merao River in Sungai Penuh City Regional Disaster Management Agency. This study uses a qualitative approach that examines an object of research by studying in its entirety and in depth rather than looking at the relationship of two or more variables, where the results of the study will be processed based on the interpretive researcher and described in a descriptive form. Data obtained through field interviews with 7 informants namely 1 key informant and 6 ordinary informants. Flood mitigation consists of prevention and mitigation, preparedness, emergency response and rehabilitation and reconstruction. Based on the existing work program, all activities have been carried out by the Sungai Penuh City Regional Disaster Management Agency in flood mitigation in Sungai Merao River Sungai Penuh which is guided by Law Number 24 Year 2007.

THE TIPLING RIVER FLOW ANALYSIS TO ASSESS MICRO HYDRO POWER AND DIVERSION BASED IRRIGATION POTENTIAL

Micro hydropower projects and diversion based irrigation projects are dependent on the amount of water flowing in the river of concern. Analyses of historical River Flow information are crucial to understand its pattern, frequency and predictability. Statistical analysis is the basis for a better scientific comprehension of the river flow system. Based on this information designing of such projects as well as making management plans for any future eventualities are possible. In this paper historical discharge information for a period of 19 years is collected and analyzed. Based on the water level and volume of discharge information of the river for the year 1995, various stage discharge rating curves are prepared. The best fitted curve is used for the estimation of the discharge for the remaining years where only the stage information is available. Daily discharge hydrographs for 19 years is prepared along with annual discharge computation for each of the 19 years of observation period. Preparation of flow duration curve helped to understand what is to be expected minimum from the river and what could be the most risky situation for a river project in this river and make necessary allowances for designing such project. Finally seasonal and monthly time series models are prepared so that the future discharge could be scientifically forecasted for predicting the future of such projects.

Existence of global solutions for isentropic gas flow with friction

In this paper, we study the existence of global entropy solutions for the Cauchy problem of the extended river flow system with a friction α(x) depending on the space variable x. First, under the boundedness of , we apply the viscosity-flux approximation method coupled with the maximum principle to obtain the a priori L∞ estimates for the approximation solutions. Second, we prove the pointwise convergence of the approximation solutions by using the compactness framework from the compensated compactness theory. Finally, as a by-product, we obtain the existence of global solutions for isentropic gas flow in the Laval nozzle with friction.

Evaluation of river connectivity based on TOPSIS model: Taking the North District Expansion Zone of Zhangjiagang Economic Development Zone in Jiangsu Province as an Example

The river system connectivity has become an important indicator of current river health assessment. The proper connectivity of river systems has the functions of allocating resources, improving water and soil environment, and preventing floods and droughts. However, it will be affected by many factors. In this paper, take Zhangjiagang, Jiangsu Province as an example, the influence degree of the structural connectivity index (expressed as static indicators) and hydroconnectivity index (expressed as static and dynamic indicators) on the connectivity of river flow system is analyzed based on the TOPSIS model. The study finds that the order of influence of each index on the connectivity of water system in the study area is: The structure connectivity index (α、 γ) is greater than hydrological connectivity index (R b 、 W p 、 R d 、 E p 、 C EN ), and the Closeness T j =(0.546, 0.546, 0.471, 0.479, 0.506, 0.519, 0.463). when analyzing the regional scale, we should consider the local conditions and consider comprehensively from the perspectives of structural connectivity and hydrological connectivity. The results of the study hope to provide theoretical basis for water system planning and management.

The acid mine drainage (AMD) impact of tailings and non-tailings on the ecosystem changes in the ModADA sedimentation area, Timika

Tailings are the parent material residues resulted from a separation process of valuable minerals containing copper, gold and silver. This separation process is carried out mechanically by destroying copper, gold and silver rocks on the Grasberg plateau. However, in the production process of tailing materials from Wanagon and Aghawagon rivers, there was also non-tailing material mixed with tailing materials. This condition cannot be avoided due to high and intensive rainfall so that non-tailing material from an ex-mine excavation in the form of overburden can flow naturally through the river flow system from the highlands to the lowlands of ModADA. Acid Mine Drainage (AMD) is one of the important impacts of mining activities that must be managed because it has an impact on the aquatic environment or groundwater, and once it has been formed it will be difficult to stop unless one of the components runs out. The study was carried out from 2005 to 2014 at several representative locations in ModADA included inactive tailings at MP 27 and MP 21, as well as active tailings at WA 225, WA 185, and WA 160. The average heavy metal content in WA 225, WA 185, WA 160 included in the criteria of class C, namely As (> 33 mg/kg), Cu (> 150 mg/kg), Pb (> 130 mg/kg), and Zn (> 460 mg/kg). Another heavy metal categorized as class B was Cd (1-5 mg/kg), while class A consisted of Cr (<43 mg/kg), Hg (<0.2 mg/kg), and Ni (<23 mg/kg). At WA 185, The ANC/MPA ratio at WA 185 < 1.5 was 0.97 (0-20 cm) and increased slightly to 1.59 (20-40 cm). The ANC/MPA ratio < 1.5 shows a higher acid-forming ability (MPA) than the ability to neutralize acid (ANC). The average heavy metal content in MP 27 is lower in concentration, except Cu which included in class C (> 150 mg/kg) which is similar to the host rock mined and involved in the tailings flow from MP 74. The Cu concentration at MP 21 decreased drastically, except for As which included in class C (> 33 mg/kg). The ANC/MPA ratio at MP 21 was 1.92 (0-20 cm) and slightly increased to 2.22 (20-40 cm), while MP 21 has the ANC/MPA ratio at 12.61 (0- 20 cm), and decreased to 4.34 (20-40 cm).

Zero run-off concept application in reducing water surface volume

Development due to population growth which is not followed by efforts to conserve water will obviously cause problems with water, situ, and the swamp area has been lost because of the construction of housing, offices and buildings. The addition of these buildings caused an increase in runoff water by many impermeable layers and reduced number of green open space, and the water could not absorb/infiltrate to soil otherwise become a surface run off. We need a way to manage and develop the storm water to overcome water runoff caused by rainwater. Zero delta Q policy is the requirement that each building should not result in an increase in water debit to the drainage system or river flow system. Water debit due to additional (runoff) development due to development) must be withheld so that the additional debit (ΔQ) is zero.The aim of this study is to reduce the surface flow of an urban settlement area by applying technology from the concept of Zero Runoff in the area. The benefits of this research are to provide alternative solutions for how to absorb and accommodate the maximum flow of surface runoff into the ground with the application of Zero Runoff concept technology.

Reliable Solution in Dynamic River Flow System Computations

Reliable Solution in Dynamic River Flow System Computations Application and limitation of various computational methods handling hydrologic runoff and varied unsteady river flow equations was studied here. Investigations were focused on many numerical aspects linear, non-linear solution of continuity and dynamic equations. A river catchment was examined, hydrometric stations, water control measures at upstream and hydrodynamic systems of river- reservoir at downstream were modeled provided evaluation and performance of water conveyance systems proposed for water resources planning and management. Application of modeling flow discharge in rivers was reviewed through a number of flow routing techniques. These classical computational methods have been widely used in water resources engineering and are subject of front line research by hydrologic and hydraulic modelers. Application of conventional and practical methods such as Muskingum-Cunge which are classified under hydrologic and hydraulic routing categories was examined for nonlinear variation of hydrodynamic parameters. Several methods including various numerical schemes were used and compared for modeling accurate unsteady flows computations. Analysis were ranked based on four criterions (consistency, stability, convergence and accuracy) examined with field observations and recorded data. Result of analysis verified that with careful description of constant and variable parameters involved in the Muskingum-Cunge model, the nonlinear terms and physical behavior of the problem was best fitted as compared by developed numerical solutions. The kinematic wave model and Hydrologic Engineering Centre (HEC) and Danish Hydraulic Institute (DHI) Mike series software were employed to verify developed fully dynamic wave model. A 42 kilometer reach length (a location between two hydrometric stations) was modeled with hydrologic and hydro-informatics parameters in Kor River were used. Comparing performances of two constant and variable Muskingum-Cunge methods, nonlinear model with variable parameters had highest reliability and accurately was used for dynamic water wave routing in water conveyance systems (especially for rivers without measuring gage stations).

Parametric Linear Stochastic Modelling of Benue River flow Process

The dynamics and accurate forecasting of streamflow processes of a river are important in the management of extreme events such as floods and droughts, optimal design of water storage structures and drainage networks. In this study, attempt was made at investigating the appropriateness of stochastic modelling of the streamflow process of the Benue River using data-driven models based on univariate streamflow series. To this end, multiplicative seasonal Autoregressive Integrated Moving Average (ARIMA) model was developed for the logarithmic transformed monthly flows. The seasonal ARIMA model’s performance was compared with the traditional Thomas-Fiering model forecasts, and results obtained show that the multiplicative seasonal ARIMA model was able to forecast flow logarithms. However, it could not adequately account for the seasonal variability in the monthly standard deviations. The forecast flow logarithms therefore cannot readily be transformed into natural flows; hence, the need for cautious optimism in its adoption, though it could be used as a basis for the development of an Integrated Riverflow Forecasting System (IRFS). Since forecasting could be a highly “noisy” application because of the complex river flow system, a distributed hydrological model is recommended for real-time forecasting of the river flow regime especially for purposes of sustainable water resources management.

Modelling scenarios to assess the effects of different agricultural management and land use options to reduce diffuse nitrogen pollution into the river Elbe

The European Water Framework Directive requires the development of measure programs, management plans and strategies to avoid the water pollution with nutrients and other harmful matters. In a case study model calculations were used to evaluate different options of land use, agricultural and water management to reduce nitrogen immissions and enhance water and nutrient retardation in the Elbe river basin. The model scenarios consider measures which are recommended to reduce nitrogen pollution like organic farming, conversion of arable land into pasture, extensivation of grassland production and set aside. Additionally the re-wetting of formerly drained areas by water management is considered where applicable. Although there are distinct differences in nitrogen leaching between the different agricultural land use and management options, the regional effects of the scenarios on the emissions from the root zone are only fair (max. 13%) because of their limited extent of application. But the targeted application of the measures in zones of high river impact risk derived from groundwater residence times and decay calculations lead to a distinct reduction of the nitrogen input into the river flow system. The combination of water management and extensivation of agricultural production can achieve a reduction of 22% (4.400 t/a) of the nitrogen immissions originated from agriculture. Areas with a high reduction potential for nitrogen immission can be identified. This can be a relevant information for the development of measure programs within the water framework directive.

Parsimonious modelling of water and suspended sediment flux from nested catchments affected by selective tropical forestry.

The ability to model the suspended sediment flux (SSflux) and associated water flow from terrain affected by selective logging is important to the establishment of credible measures to improve the ecological sustainability of forestry practices. Recent appreciation of the impact of parameter uncertainty on the statistical credibility of complex models with little internal state validation supports the use of more parsimonious approaches such as data-based mechanistic (DBM) modelling. The DBM approach combines physically based understanding with model structure identification based on transfer functions and objective statistical inference. Within this study, these approaches have been newly applied to rainfall-SSflux response. The dynamics of the sediment system, together with the rainfall-river flow system, were monitored at five nested contributory areas within a 44 ha headwater region in Malaysian Borneo. The data series analysed covered a whole year at a 5 min resolution, and were collected during a period some five to six years after selective timber harvesting had ceased. Physically based and statistical interpretation of these data was possible given the wealth of contemporary and past hydrogeomorphic data collected within the same region. The results indicated that parsimonious, three-parameter models of rainfall-river flow and rainfall-SSflux for the whole catchment describe 80 and 90% of the variance, respectively, and that parameter changes between scales could be explained in physically meaningful terms. Indeed, the modelling indicated some new conceptual descriptions of the river flow and sediment-generation systems. An extreme rainstorm having a 10-20 year return period was present within the data series and was shown to generate new mass movements along the forestry roads that had a differential impact on the monitored contributory areas. Critically, this spatially discrete behaviour was captured by the modelling and may indicate the potential use of DBM approaches for (i) predicting the differential effect of alternative forestry practices, (ii) estimating uncertainty in the behaviour of ungauged areas and (iii) forecasting river flow and SSflux in terrain with temporal changes in rainfall regime and forestry impacts.

NONLINEAR MODELING AND PREDICTION OF A RIVER FLOW SYSTEM1

ABSTRACT: Model estimation and prediction of a river flow system are investigated using nonlinear system identification techniques. We demonstrate how the dynamics of the system, rainfall, and river flow can be modeled using NARMAX (Nonlinear Autoregressive Moving Average with eXogenuous input) models. The parameters of the model are estimated using an orthogonal least squares algorithm with intelligent structure detection. The identification of the nonlinear model is described to represent the relationship between local rainfall and river flow at Enoree station (inputs) and river flow at Whitmire (output) for a river flow system in South Carolina.

A deuterium-calibrated groundwater flow model of a regional carbonate-alluvial system

The White River Flow System (WRFS), a regional carbonate-alluvial groundwater system in southeastern Nevada, U.S.A., contains large amounts of water in storage, especially in the underlying carbonate reservoir. As the population of Nevada grows, it may become necessary to tap the resources of this and other regional carbonate systems. Because of the depth to the carbonate reservoir and, until now, lack of motivation to collect detailed hydrogeological data on it, the state of knowledge of flow in the carbonate system is poor. However, a simple mixing-cell flow model of the WRFS can be constructed and calibrated with the spatial distribution of the stable isotope deuterium. This type of model subdivides the system into carbonate and alluvial cells and routes water and deuterium through the entire cell network. It provides estimates of recharge rates, groundwater ages and volumes of water in storage. Transience in recharge rates and their deuterium signatures are unaccounted for by the model. The lack of constraints on the system mandates the calibration of three different flow scenarios, each of which differs slightly from the other. Despite these differences, some consistent quantitative results are obtained. Foremost among these are: (1) the carbonate aquifer may contain as much as 752 km 3 of water in storage; (2) recharge from the Sheep Range to Coyote Spring Valley is at least 90% greater than previously believed; (3) Lower Meadow Valley is part of the WRFS and contributes underflow to Upper Moapa Valley; (4) underflow with an average value of 0.163 m 3 s −1 flows westward out of the system along the Pahranagat Shear Zone; (5) recharge to the alluvial system is greater than that to the carbonate system; (6) groundwater mean ages range from 1600 to 34 000 years, with the oldest waters exceeding 100 000 years old. The results also demonstrate that deuterium can be used to calibrate simple flow models and provide groundwater ages. Despite the uncertainties and lack of constraints in mixing-cell models, they provide first approximations to information which, until now, has been difficult, if not impossible, to obtain. These models are especially useful for analyzing sparse-data systems, testing different flow hypotheses with minimal effort, providing ranges in parameter estimates, guiding future data collection and serving as precursors for the development of more sophisticated models.