River Flow Measurements Research Articles

High-performance approach for estimating stage-discharge curves in the open channels

The stage-discharge relationship is one of the frequently used methods for continuous river flow measurement. In the management of water resources and flood control, the accuracy of the rating curve is a key priority. Various methods have been proposed for estimating the stage-discharge curves in open channels, including the model of Ahmadi et al. (2017) in which the rating curve was identified by utilizing the information of discharge at a referenced water level. In the present study, a novel approach was taken to improve that model by modifying its basic assumptions and employing multi-objective optimization. To this end, multivariate relationships were presented to determine the actual mean velocity in the flow cross-section. The unknown exponents of the proposed relationships were obtained by using the second version of the Strength Pareto Evolutionary Algorithm (SPEA2), and the appropriate equation was selected by applying the TOPSIS (Technique for Order Preferences by Similarity to an Ideal Solution) approach. The validity of the proposed method was assessed across 6 artificial and 6 natural hydraulic cross-sections. Results showed a close agreement between the estimated and observed data. In the next step, the results of the proposed method were compared with those of the previous model using the Mann-Whitney U test. The results demonstrated that the proposed model was more efficient than the previous one.

Listrik mikro hidro berdasarkan Potensi debit andalan sungai batanghari kota jambi

The city of Jambi is an area batanghari river, the study of the utilization of renewable energy, especially hydro power through the tributaries should be considered for the planning of Micro Hydro Power Plant (PLTMH). Water conditions that can be utilized as electricity generating resources have a certain flow capacity and altitude of their drainage system. A major problem in hydroelectric generation is the availability of river water discharge as a propulsion energy. Therefore, certain techniques are needed to predict the potential flow of river water at all times or the river's main discharge that can be used for hydro-electric power generation, no long-term rainfall and critical watershed conditions can cause water flow the stream becomes small and even becomes dry. Manual river flow measurements over time can only represent the volume of river flow at the time of measurement. Changes that occur due to the occurrence of rain at a later time, or decrease in river discharge due to decreased soil water savings, can not be monitored properly it is necessary to plan a continuous discharge for the capacity of generator turbine rotation by calculating the electrical capacity of the generator which can be generated optimally

Hhaynu micro hydropower scheme: Mbulu – Tanzania comparative river flow velocity and discharge measurement methods

The objective of the study has been to determine the river discharge by measuring the river flow velocity using two different measurement methods together with the area method and compare the accuracy of the results.Two river flow velocity measurement methods were used, the floating method and the use of current meter. In floating method a floating object was used to determine the water flow velocity on the surface by allow a float to move a distance of 1 m along the river and record the time it takes to travel that distance in seconds. Ten readings were taken and manually recorded and the flow velocity was determined by taking the distance travel by the float (1 m) divide by the time taken by the float (in seconds). On the other hand, the current meter method measure directly the average flow velocity across the river depth, twenty readings were taken and recorded manually and the average velocity were calculated. The use of current meter display flow velocity directly without the need of calculations.The result shows that both methods produce very close value, but the floating method have displayed higher value of around + 2% than current meter method which is a good value, despite the fact that floating method measures the surface velocity and the use of calculation. Many literature highlighted the accuracy of flow velocity measurement using current meter due to the fact that it measures the average velocity across the river, but from the findings when the floating method flow velocity measurement is properly applied it will produce as accurate results as the current meter with a fraction of cost in terms of instrument cost and expertise requirement in measurements.The floating method flow velocity measurement method could be applicable as alternative to current meter in micro hydropower projects river flow measurements in rural areas of developing countries with limited funding and local expertise.

Applying adaptive LS-PIV with dynamically adjusting detection region approach on the surface velocity measurement of river flow

An image based surface velocity measurement of river flow that applies the adaptive large-scale particle Image velocimetry (LS-PIV) with dynamically adjusting detection region (DADR) approach is presented in this research. The image based measurement is a safe and efficient method. However, the flow conditions, weather or environment changes caused this type of measurement was hard to adapt each situation. In this paper, the DADR method was proposed to determine the better detection region whenever the flow condition changed. The proposed adaptable interrogation area (IA) size determining algorithm was applied to automatically correct the IA size and overcome the lower signal to noise rate (SNR) and higher errors produced by the conventional measurement with the fixed IA under varied environments. Based on the experimental results, our proposed approaches are accurate, robust and adaptable enough to overcome multiple flow and weather conditions presented in this paper.

A Muskingum-based methodology for river discharge estimation and rating curve development under significant lateral inflow conditions

Quite often the discharge at a site is estimated using the rating curve developed for that site and its development requires river flow measurements, which are costly, tedious and dangerous during severe floods. To circumvent the conventional rating curve development approach, Perumal et al. in 2007 and 2010 applied the Variable Parameter Muskingum Stage-hydrograph (VPMS) routing method for developing stage-discharge relationships especially at those ungauged river sites where stage measurements and details of section geometry are available, but discharge measurements are not made. The VPMS method enables to estimate rating curves at ungauged river sites with acceptable accuracy. But the application of the method is subjected to the limitation of negligible presence of lateral flow within the routing reach. To overcome this limitation, this study proposes an extension of the VPMS method, henceforth, known herein as the VPMS-Lin method, for enabling the streamflow assessment even when significant lateral inflow occurs along the river reach considered for routing. The lateral inflow is estimated through the continuity equation expressed in the characteristic form asadvocated by Barbetta et al. in 2012.The VPMS-Lin, is tested on two rivers characterized by different geometric and hydraulic properties: 1) a 50km reach of the Tiber River in (central Italy) and 2) a 73km reach of the Godavari River in the peninsular India. The study demonstrates that both the upstream and downstream discharge hydrographs are well reproduced, with a root mean square error equal on average to about 35 and 1700m3s−1 for the Tiber River and the Godavari River case studies, respectively. Moreover, simulation studies carried out on a river stretch of the Tiber River using the one-dimensional hydraulic model MIKE11 and the VPMS-Lin models demonstrate the accuracy of the VMPS-Lin model, which besides enabling the estimation of streamflow, also enables the estimation of reach averaged optimal roughness coefficients for the considered routing events.

Assessing glacier melt contribution to streamflow at Universidad Glacier, central Andes of Chile

Abstract. Glacier melt is an important source of water for high Andean rivers in central Chile, especially in dry years, when it can be an important contributor to flows during late summer and autumn. However, few studies have quantified glacier melt contribution to streamflow in this region. To address this shortcoming, we present an analysis of meteorological conditions and ablation for Universidad Glacier, one of the largest valley glaciers in the central Andes of Chile at the head of the Tinguiririca River, for the 2009–2010 ablation season. We used meteorological measurements from two automatic weather stations installed on the glacier to drive a distributed temperature-index and runoff routing model. The temperature-index model was calibrated at the lower weather station site and showed good agreement with melt estimates from an ablation stake and sonic ranger, and with a physically based energy balance model. Total modelled glacier melt is compared with river flow measurements at three sites located between 0.5 and 50 km downstream. Universidad Glacier shows extremely high melt rates over the ablation season which may exceed 10 m water equivalent in the lower ablation area, representing between 10 and 13 % of the mean monthly streamflow at the outlet of the Tinguiririca River Basin between December 2009 and March 2010. This contribution rises to a monthly maximum of almost 20 % in March 2010, demonstrating the importance of glacier runoff to streamflow, particularly in dry years such as 2009–2010. The temperature-index approach benefits from the availability of on-glacier meteorological data, enabling the calculation of the local hourly variable lapse rate, and is suited to high melt regimes, but would not be easily applicable to glaciers further north in Chile where sublimation is more significant.

Proof‐of‐concept for low‐cost and non‐contact synoptic airborne river flow measurements

ABSTRACTThis article presents an example for an image-based method to determine a small rivers’ surface velocity field, bathymetry, and its flow discharge derived thereof. While common river measurement techniques typically need to be in contact with the waterbody, at least to measure transects of water depths, the new approach is completely without direct contact to water. The scenery is recorded by an off-the-shelf action camera mounted to a low-cost quadcopter. During the analysis, image frames are orthorectified and georeferenced by an approach that combines structure from motion and multiview stereo algorithms. Particle image velocimetry based on tracer particles present in the river is utilized to compute flow velocities. Instantaneous surface flow velocity fields are used to compute the mean velocity field as well as to derive water depth estimates by turbulence metrics. The latter provide a basis to verify the bathymetry gained from the reconstructed subaqueous three-dimensional scenery. Finally, flow discharge is estimated based on the above findings. The new method will expand the scientific knowledge on river flows for diverse disciplines such as hydrology, biology, and river engineering. Due to the low cost of the measurement instrumentation being deployed, it has the potential to be applied by a broad user group.

Correction of bifurcated river flow measurements from historical data: Paving the way for the Teesta water sharing treaty

In this paper, we consider an estimation problem arising in the measurement of bifurcated flow of the Teesta, a trans-boundary river flowing through India and Bangladesh. The location of measurement is an Indian Barrage, where a part of the flow is diverted from the main stream to a canal. The flows through the two channels are regulated by different control structures and are measured indirectly from the height of the water level and the dimensions of the control structures. The computational formula for the measurement involves a hydrological constant used as a multiplier. Empirical findings indicate that incorrect multipliers are currently used in the computational formula for the two channels. For implementing any water sharing treaty between the two countries, the measurements need to be brought to a common scale. For this purpose, we present a model with carefully considered assumptions to estimate the correction factor. The model permits diagnostic tests for validation of the assumptions. We provide a nonparametric and consistent estimator of the desired factor. Analysis of historical flow data shows that a main stream flow measured as 100 cumec would be measured as 76 cumec if it is diverted through the canal. Adjustment of emerging measurements through this finding would help the governments of India and Bangladesh to effectively implement and monitor any water sharing agreement.

Incidental potable water reuse in a Catalonian basin: living downstream

A preliminary assessment of incidental potable water reuse (IPR) in the Llobregat River basin has been conducted by estimating the dilution factor of treated effluent discharges upstream of six river flow measurement sections. IPR in the Llobregat River basin is an everyday occurrence, because of the systematic discharge of treated effluents upstream of river sections used as drinking water sources. Average river flows at the Sant Joan Despí measurement section increased from 400,000 m3/d (2007) to 864,000 m3/d (2008) and to 931,000 m3/d (2013), while treated effluent discharges upstream of that section ranged from 109,000 m3/d to 114,000 m3/d in those years. The highest degree of IPR occurs downstream of the Abrera and Sant Joan Despí flow measurement sections, from where about half of the drinking water supplied to the Barcelona Metropolitan Area is abstracted. Based on average annual flows, the likelihood that drinking water produced from that river stretch contained treated effluent varied from 25% (2007) to 13% (2008) and to 12% (2013). Water agencies and drinking water production utilities have strived for decades to ensure that drinking water production satisfies applicable quality requirements and provides the required public health protection.

Orographic Precipitation in Coastal Southern Chile: Mean Distribution, Temporal Variability, and Linear Contribution

AbstractThe Nahuelbuta Mountains (NM) are a semielliptical massif 1300 m high in coastal southern Chile (37°–38°S) facing frontal storms that move from the Pacific. Mean precipitation between 900 and 1200 mm yr−1 is observed in the surrounding lowland, but river flow measurements suggest values ≥3000 mm yr−1 atop the mountains. To verify and characterize such marked orographic enhancement, 15 rain gauges were deployed around and over the NM. The observations were supplemented by a high-resolution WRF simulation and linear theory (LT) modeling during the winter of 2011. The estimated mean precipitation increases gradually from offshore (~1000 mm yr−1) to the north-facing foothills (2000 mm yr−1). The precipitation rapidly increases in the upslope sector to reach ~4000 mm yr−1 over the northern half of the NM elevated plateau, and decreases farther south to reach background values 20–30 km downstream of the mountains. The upstream (downstream) orographic enhancement (suppression) was relatively uniform among storms when considering event accumulations but varied substantially within each storm, with larger modifications during pre- and postfrontal stages and minor modifications during the brief but intense frontal passage. WRF results are in good agreement with observations in terms of seasonal and daily mean rainfall distributions, as well as temporal variability. Given its linear, steady-state formulation, the LT model cannot resolve rainfall variability at short (hourly) time scales, which in WRF is at least characterized by transient, mesoscale rainbands. Nonetheless, the rainbands are mobile so the accumulation field at monthly or longer time scales produced by the linear model is remarkably similar to its WRF counterpart.

Estimation of discharge in rivers by different artificial neural network algorithms: case of the Algerian Coastal basin

River discharge estimation is fundamental for a large number of engineering applications. The rating curve of a hydrometric station, which permits the establishment of a relationship between water level h and flow rate Q at a given cross-section, is the methodology most frequently used for continuous river flow measurements. To properly develop rating curves, discharges must be measured at all representative stages, using at least 10 to 12 points covering the range of low to high flows (Kennedy 2001). In the Algerian rivers, the bed is unstable, it is constantly in motion and characterized by a strong rate of sediments transported (Salhi et al. 2013), so the stage–discharge relationship is re-callipered more than four times per year (ANRH, 2009). Whenever, the river crosssection changes, the old data and rating curve become useless and discharge calculations must wait until enough new data are collected to establish a new empirical rating. Consequently, long series of levels are frequently available without the corresponding discharge values. During the transition period when the change is occurring, the discharge is calculated from field measurements of velocity and cross-section gauging (WMO 2008). These require much time and effort and are usually not done in flood conditions because of the dangers and the difficulty in activating the measurement team in due time, which is very frequent in Algerian rivers. In these cases, water level–runoff models can be used as an alternative solution. This study compared three artificial neural networks (ANN) algorithms to calibrate a water level–runoff model from two hydrometrics stations in the Algerian Coastal basin. These algorithms, the Levenberg-Marquard (ANN_LM), scaled conjugate gradient (ANN_SCG), and resilient back-propagation (ANN_RP), were applied to the tangent sigmoid transfer function. The input vector consisted of level [H(t)], and antecedents levels [H(t−1), H(t−2) and H(t−3)]. The algorithms were trained and validated by cross-validation using the limnigrammes provided and the realized gauging.

Water management plan for olive orchards in a semi-mountainous area of Crete, Greece

<div> <p>In the present work the physically based distributed rainfall–runoff modeling system, MIKE SHE, is used to simulate the surface runoff at a semi-mountainous impermeable area of Tavronitis River basin in Crete-Greece.  The objective of this surface flow model is to develop an appropriate irrigation plan for olive trees. For the model calibration, a simulation time of one year (01/09/2000 - 31/08/2001) was considered, while for the model verification a two-year period (01/09/2001 - 31/08/2003). During these periods river flow measurements were obtained at two specified locations. These measurements were employed as targets for calibration and verification of the surface flow model. After the successful calibration and validation processes, the 2D maps of the overland flow were produced. Using these maps, the locations of significant surface water accumulation in the study region and for a specific time period were identified. Next, these locations were proposed for the construction of potential small hydraulic structures (dam or/and reservoir), for covering the irrigation needs of olive trees in the study area. </p> </div> <p> </p>

On the application of remotely operated drive with ADCP in rivers

High-flow data are among the most important types of information for river flood control and water management. An acoustic Doppler current profiler (ADCP), tethered boat, and remotely operated drive are designed as an alternate flow measurement system. Regular- and high-flow measurements were conducted with traditional Price current meter and ADCP to evaluate the accuracy of measurement. The results indicate that the ADCP data are consistent with the current-meter data. Moreover, the ADCP measurements successfully represented the rising and falling stages of the typhoon flood. These results demonstrate that the developed measurement system is practical for river flow measurement.

New Method of Image Background Suppression Based on Soft Morphology and Retinex Theory

A new river flow measurement method based on graphic process has been proposed recently, which gets the velocity in optical imaging modality through measuring the continuous displacement of floating debris, then reconstructs a two-dimensional river surface velocity field by using the velocity of floating debris, and computes the section flow at last. However, the surface optical images have not only lights of target information, but also surface optical noise. It is difficult for reliable and stable continuous displacement detection of complex small observation target, which occupies only a small number of pixels comparing to a large field imaging area and has complex optical reflection properties. To solve this problem, this paper presents a background suppression method based on soft morphology and Retinex theory. Soft morphology is firstly used for the opening operation of the image, and then Retinex theory is used for optimal estimation of image incident component to suppress background of image. Finally, the simulations show that our method is superior to gray morphology and soft morphology on the performance of targets enhancement, noise filtering, and background suppression, and it has better background and targets discrimination quality subjective evaluation and higher signal-to-clutter ratio.

RIVER FLOW CONDITIONS AND DYNAMIC STATE ANALYSIS OF PAHANG RIVER

Pahang River (Sg. Pahang) is the longest river in Peninsular Malaysia. Flood is a common event in Pahang River Basin during wet season which triggered by monsoon season. The hydrodynamic study of Pahang River should be well understood especially when it is a target of northeast monsoon which influenced the Pahang River Basin every year (from November to March). 17 river cross section stations were selected and used to measure its drainage capacity, hydraulic parameters and estimation of flow discharge. Long term (1980 to 2009) variation of hydrologic data series comprised of river flow, river stage and rainfall data were analyzed based on the Department of Irrigation and Drainage (DID) Malaysia record. Monthly rainfall was recorded from Sg. Yap, Temerloh and Lubuk Paku Rainfall Stations. Two hydrologic sampling trips had been carried out; first sampling on January 2010 and second sampling on February 2010. The study indicates that velocity and river flow measurement during first sampling ranged from 0.308 to 0.582 m sec-1 and 153.282 to 439.684 m3 sec-1. Meanwhile, during second sampling, the velocity and river flow ranged from 0.217 to 0.484 and 52.071 to 304.485 m3 sec-1, respectively. Floods were occurred annually at Pahang River especially during northeast monsoon, these events are expected to be stimulated by the inconsistent condition of width and depth along Pahang River which finally create sedimentation and meandering characteristic.

Evaluation of a Simple Hydraulic Resistance Model Using Flow Measurements Collected in Vegetated Waterways

A simple idealized model to describe the hydraulic resistance caused by vegetation is compared to results from flow experiments conducted in natural waterways. Two field case studies are considered: fixed-point flow measurements in a Green River (case 1) and vessel-borne flow measurements along a cross-section with floodplains in the river Rhine (case 2). Analysis of the two cases shows that the simple flow model is consistent with measured flow velocities and the present vegetation characteristics, and may be used to predict a realistic Manning resistance coefficient. From flow measurements in the river floodplain (case 2) an estimate was made of the equivalent height of the drag dominated vegetation layer, as based on measured flow characteristics. The resulting height corresponds well with the observed height of vegetation in the floodplain. The expected depth-dependency of the associated Manning resistance coefficient for could not be detected due to lack of data for relatively shallow flows. Furthermore, it was shown that topographical variations in the floodplain may have an important impact on the flow field, which should not be mistaken as roughness effects.

Assessing rating-curve uncertainty and its effects on hydraulic model calibration

Abstract. This study considers the overall uncertainty affecting river flow measurements and proposes a framework for analysing the uncertainty of rating-curves and its effects on the calibration of numerical hydraulic models. The uncertainty associated with rating-curves is often considered negligible relative to other approximations affecting hydraulic studies, even though recent studies point out that rating-curves uncertainty may be significant. This study refers to a ~240 km reach of River Po and simulates ten different historical flood events by means of a quasi-twodimensional (quasi-2-D) hydraulic model in order to generate 50 synthetic measurement campaigns (5 campaigns per event) at the gauged cross-section of interest (i.e. Cremona streamgauge). For each synthetic campaign, two different procedures for rating-curve estimation are applied after corrupting simulated discharges according to the indications reported in the literature on accuracy of discharge measurements, and the uncertainty associated with each procedure is then quantified. To investigate the propagation of rating-curve uncertainty on the calibration of Manning's roughness coefficients further model simulations are run downstream Cremona's cross-section. Results highlight the significant role of extrapolation errors and how rating-curve uncertainty may be responsible for estimating unrealistic roughness coefficients. Finally, the uncertainty of these coefficients is analysed and discussed relative to the variability of Manning's coefficient reported in the literature for large natural streams.

Pharmacokinetic modelling of multi-decadal luminescence time series in coral skeletons

As corals grow, they incorporate chemical indicators of seawater conditions into their aragonite skeleton after they have traversed an outer living tissue layer. Long-lived, massive coral skeletons can record decade- and century-long time series of seawater status. One such environmental clue is luminescence intensity which can correspond to river flow patterns and has been attributed to humic acid incorporation. Seawater humic acid levels are linked to river flow as rainfall extracts them from catchment soils to then flow into rivers and coastal seas. However, discrepancies exist when validating coral luminescence records against river flow data with intense luminescence sometimes occurring in the absence of increased flows. This contributes to uncertainty when reconstructing pre-instrumental river flows and rainfall from coral luminescence. Here we demonstrate that a major portion of coral core luminescence time series can be explained using a single-compartment, pharmacokinetic model that incorporates river flow measurements as the equivalent of drug dose. The model was robust for luminescence series in corals from near-shore reefs regularly influenced by river flow. The model implies that after floods, a proportion of subsequent luminescence peaks can be derived from the initial flood. This explains why some luminescence peaks after floods often do not correspond to additional significant river flows. This provides the first mechanism-based explanation for temporal changes in coral skeleton luminescence that incorporates a mathematical link between two independent time series making this proxy even more robust for reconstructing river flow and rainfall.

How Well Do Large-Scale Models Reproduce Regional Hydrological Extremes in Europe?

AbstractThis paper presents a new methodology for assessing the ability of gridded hydrological models to reproduce large-scale hydrological high and low flow events (as a proxy for hydrological extremes) as described by catalogues of historical droughts [using the regional deficiency index (RDI)] and high flows [regional flood index (RFI)] previously derived from river flow measurements across Europe. Using the same methods, total runoff simulated by three global hydrological models from the Water Model Intercomparison Project (WaterMIP) [Joint U.K. Land Environment Simulator (JULES), Water Global Assessment and Prognosis (WaterGAP), and Max Planck Institute Hydrological Model (MPI-HM)] run with the same meteorological input (watch forcing data) at the same spatial 0.5° grid was used to calculate simulated RDI and RFI for the period 1963–2001 in the same European regions, directly comparable with the observed catalogues. Observed and simulated RDI and RFI time series were compared using three performance measures: the relative mean error, the ratio between the standard deviation of simulated over observed series, and the Spearman correlation coefficient. Results show that all models can broadly reproduce the spatiotemporal evolution of hydrological extremes in Europe to varying degrees. JULES tends to produce prolonged, highly spatially coherent events for both high and low flows, with events developing more slowly and reaching and sustaining greater spatial coherence than observed—this could be due to runoff being dominated by slow-responding subsurface flow. In contrast, MPI-HM shows very high variability in the simulated RDI and RFI time series and a more rapid onset of extreme events than observed, in particular for regions with significant water storage capacity—this could be due to possible underrepresentation of infiltration and groundwater storage, with soil saturation reached too quickly. WaterGAP shares some of the issues of variability with MPI-HM—also attributed to insufficient soil storage capacity and surplus effective precipitation being generated as surface runoff—and some strong spatial coherence of simulated events with JULES, but neither of these are dominant. Of the three global models considered here, WaterGAP is arguably best suited to reproduce most regional characteristics of large-scale high and low flow events in Europe. Some systematic weaknesses emerge in all models, in particular for high flows, which could be a product of poor spatial resolution of the input climate data (e.g., where extreme precipitation is driven by local convective storms) or topography. Overall, this study has demonstrated that RDI and RFI are powerful tools that can be used to assess how well large-scale hydrological models reproduce large-scale hydrological extremes—an exercise rarely undertaken in model intercomparisons.

Developing winter flow rating relationships using slope‐area hydraulics

AbstractDespite recent advances in instrumentation and modelling methods, accurate determination of river discharge under an ice cover still requires direct measurement. Published flows at hydrometric gauging stations are based on interpolation between a few measurements that are carried out during each winter. The feasibility of using slope‐area hydraulics to develop discharge‐stage rating relationships is explored at two stations, Peace River at Peace Point and Mackenzie River at Arctic Red River. Records at both gauges contain key information for understanding local ice jamming processes, which are known to control the long‐term maintenance of the aquatic ecosystems in the respective deltas. For each site, the variations of reach‐average hydraulic parameters with stage are first determined from several nearby cross‐sections. This information is then used to calculate hydraulic resistance characteristics during the ice season based on archived discharge measurement data, which also include ice cover thickness. The Peace River flow measurements indicate a well‐defined seasonal variation in hydraulic resistance, with the exception of years with large slush deposits under the solid‐ice sheet. Slush effects are negligible at the Mackenzie River gauge site, but the stage‐flow relationship is complicated by a variable water surface slope, a result of downstream control by the Beaufort Sea. This feature is most pronounced during the pre‐breakup period when flows are rising sharply and renders flow estimation uncertain. A nearby water‐level gauge would help quantify the slope and increase confidence in winter flow estimates. Copyright © 2010 in the right of Canada.