Integrated Engineering, Environmental, and Economical Modelling of Micro Hydro Plant (MHP) Production

The use of renewable energy has commonly concentrated on energy production through wind engines and solar panels. Nowadays, the micro-hydropower (MHP) plant has a great challenge as an important contributor to energy systems. Indonesia has the potential natural resources to develop that power plant, in the form of the river where is abundant throughout all provinces. The research aims to address solving issues regarding deficit energy by renewable energy production. The environmental and hydrological approaches were used to determine the location to obtain the optimal and proper utilization of MHP. The analysing from all modelling creates an economical assessment of MHP energy production. The result recommends MHP with the capacity of 2 x 4.0 MW and a total discharge of 14.30 m3/second whereas design flood discharge is 813.47 m3/second (Q100 year). The implementation of MHP is an effort to achieve independent energy in the region.

Conduit and fracture flow characteristics of Pınarbaşı spring, Central Taurus Region, Seydişehir, Turkey

This study was conducted to investigate the flow and storage mechanisms of a karst aquifer located at the central Taurus Mountains, Turkey. As the biggest discharge point of the aquifer system, the flow characteristics are investigated at Pinarbaşi spring by using recession and time-series analyses. Continuous water level measurements are taken from the spring and are converted to flow rate by using a rating curve. The spring flows for 7 months (December 2014 – July 2015) and dries up for the rest of the year. Six individual recession periods are investigated and analyzed in the discharge time series. The recession coefficients (between 0.029 day-1 and 0.695 day-1) show that the flow within the aquifer system is mainly controlled by large open conduit and partly fracture porosity. The peak discharge is measured as 7.08 m3/s, and the maximum storage within the aquifer is calculated as 3.15 million m3. The continuous discharge data of the spring were evaluated combined with daily rainfall, temperature, electrical conductivity, and amount of suspended sediment in the water. Also a dye-tracing test was also applied to obtain the recharge-discharge relationship and porosity type of the aquifer system. Statistical tests on discharge hydrograph and tracer test showed that the memory of the karst aquifer was found to be about 3 days in the DJF period and about 15 days in the MAM period. The average elevation of the recharge area of the spring was determined to be 1,490 m by using stable isotope data of snow samples and was validated by dye tracer test made via the swallow hole in the recharge area. The total discharge for the year 2015 is estimated at 16.2 million m3 that approximately 25% of the total discharge is caused by snowmelt.

EXPERIMENTAL AND NUMERICAL STUDIES OF PRESSURE AND GAP LENGTH EFFECTS ON ENERGY DEPOSITION IN SPARK DISCHARGE

A study of the influence of the discharge gap length and the initial gas pressure on the energy deposition into the discharge channel was done. The study was conducted at the same total discharge energy. It is experimentally shown that the connection of the voltage probe to the discharge circuit significantly affects the discharge current. The determination of the energy deposited into the spark channel is based on the results of numerical simulation of the spark channel development. Experimentally measured discharge currents at different pressures and the gap length were used as initial data for the calculation. Based on the obtained results, it is determined which of the factors (the initial pressure or the gap length) has the strongest influence on the energy input into the spark channel.

Effect of Friction Coupling on Discharge Velocity Profiles and Force Chain Distribution of Maize Particles in Silos

The evolution mechanism of discharge velocity profiles and force chain distribution of maize particles in silos was studied based on the interaction between internal and external rolling friction of particles. Through EDEM, the silo and maize grain models were established for unloading simulation, whose flow pattern was compared with the silo unloading test to verify the rationality of the simulation. By slice observation, we compared and analyzed the time evolution rules of particle mesoscopic parameters under different friction conditions. The results show that the larger the interparticle friction coefficient is, the longer the total discharge time is and the smaller the coefficient of rolling friction between particles, the earlier the particle flow from mass flow to funnel flow. For silos with the funnel, the reduction of interparticle friction will change the limit between the mass flow and the funnel flow, thus increasing the area of the funnel flow. When the coefficient of rolling friction increases, the vertical velocity and angular velocity of the particle near the silo middle increase. However, the effects of internal and external friction coupling on the vertical velocity of the side particle, the horizontal velocity of the whole particle, and the spatial distribution and probability distribution of the force chain are more significant.

The Drainage Design on Umban Sari Street from STA 0+500 until STA 0+750 Rumbai Sub-District Pekanbaru City

Drainage is an important part of city building. Drainage’s function is to channel the water stream in order to prevent pudde on road surface which will harm the road construction. Therefore, an adequate drainage is needed to contain the rainwater and waste discharge and channel it to the sewer. The purpose of this research is to calculate the appropriate and adequate canal drainage capacity and dimension so that puddles and floods will less likely to happen in the next 10 years on the research sector. Methods used is gumbel, arithmetic and rational. The result of research is economical section’s trapezoidal drainage design which dimension needed is H = 1,14 m. B = 1,41 m, T = 2,55 m and w = 0,75 m. Therefore can be concluded that designed drainage capacity plan on sector Umban Sari street is capable to contain rainwater discharge, because it adjusted to total discharge plan of 0,55509 m3/s and total discharge plan of 0,246 m/s. The suggestion from this research so that this planned drainage can function optimally is all party concerned will have to maintenance the drainage periodically, by doing checking, cleaning and not littering.

Fusion of Multi-Satellite Data and Artificial Neural Network for Predicting Total Discharge

As research on the use of satellites in combination with previous hydrological monitoring techniques increases, interest in the application of the machine-learning approach to the prediction of hydrological variables is growing. Ground-based measurements are often limited due to the difficulties in measuring spatiotemporal variations, especially in ungauged areas. In addition, there are no existing satellites capable of measuring total discharge directly. In this study, Artificial neural network (ANN) machine-learning approaches are examined for the prediction of 0.25° total discharge data over the Korean Peninsula using the data fusion of multi-satellites, reanalysis data, and ground-based observations. Terrestrial water storage changes (TWSC) of the Gravity Recovery and Climate Experiment (GRACE) satellite, precipitation of the tropical rainfall measuring mission (TRMM), and soil moisture storage and average temperature of the global land data assimilation system (GLDAS) models are used as ANN model input data. The results demonstrate the relatively good performance of the ANN approach for predicting the total discharge in terms of the correlation coefficient (r = 0.65–0.95), maximum absolute error (MAE = 13.28–20.35 mm/month), root mean square error (RMSE = 22.56–34.77 mm/month), and Nash-Sutcliff efficiency (NSE = 0.42–0.90). The precipitation is identified as the most influential input parameter through a sensitivity analysis. Overall, the ANN-predicted total discharge shows similar spatial patterns to those from other methods, while GLDAS underestimates the total discharge with a smaller dynamic range than the other models. Thus, the potential of the ANN approach described herein shows promise for predicting the total discharge based on the data fusion of multi-satellites, reanalysis data, and ground-based observations.

Potensi Debit Aliran Lokal Waduk Saguling Menggunakan Model Hujan Limpasan

Saguling reservoir is one of the three largest reservoirs in the Citarum River Basin. The water source of its reservoir originates from Upper Citarum river basin, with gauging station located in Citarum-Nanjung and local discharge from tributaries around the reservoir. The problem is there is no observation of local discharge from the tributaries, thus its potential is estimated. The purpose of this study is to analyze the potential of local discharge with the Hydrology Engineering Center-Hydrologic Modeling System (HEC-HMS) model. The HEC-HMS Rainfall-runoff method is used for calculating the potential of the local discharge that flows into Saguling resevrvoir. The parameters used in the model are deficit constant (loss parameter), linear reservoir (baseflow parameter), dan lag time (transform parameter). Rainfall-runoff model produced good calibration values for Citarum-Nanjung Gauging Station with R2 of 0.8 and the Nash-Sutcliffe efficiency (NSE) value of 0.788. The verification result carried out in Saguling reservoir gives NSE of 0.8343 and R2 value of 0.83. The simulation shows that the potential discharge from local river contributes about 21.64% of the total discharge that enters into the reservoir with monthly dependable flow for power plants, Q80 and Q85 values at 8,23 m3/s and 5,69 m3/s, respectively. The average discharge of local rivers can generate electricity of 3.89 MW - 162 MW.Keywords: Local discharge, rainfall runoff, potential discharge, Saguling reservoir

Event runoff calibration with LISEM in a recently burned Mediterranean forest catchment.

<p>Wildfires are known to change post-fire hydrological response as a consequence of fire-induced changes such as soil water repellence (SWR). SWR has also been identified as a key factor determining runoff generation at plot and slope scale studies, in which soil moisture content (SMC) has been presented as dependent variable. However, these relationships have not been established at catchment scale yet, mainly due to the inherent difficulties in monitoring post-fire hydrological responses at this scale and in finding relationships between these events with SWR point (time and space) measurements. To fulfil these knowledge gaps, the present study aims to advance the knowledge on post-fire hydrological response by simulating quick flows from a small burned catchment using a physical event-based soil erosion model (OpenLISEM).</p><p>OpenLISEM was applied to simulate sixteen events with two distinct initial soil moisture conditions (dry and wet), in which the model calibration was performed by adjusting Manning’s n and saturated soil moisture content (theta<sub>s</sub>). Considering that manual calibration resulted in distinct Manning’s n for wet and dry conditions, while thetas required an individual calibration for each event, an alternative parameterization of theta<sub>s</sub> was created by means of linear regressions, for all the events together (“overall”), and for wet and dry events separately (“wet” and “dry”). Model performance was evaluated at the outlet, while hillslope predictions were compared with runoff data from micro-plots that were installed at 3 of the hillslopes (Vieira et al., 2018).</p><p>The validation of field data at micro-plot scale revealed several comparability limitations attributed to the time-step of the field data (1- to 2-weekly) in comparison to the duration of the events (170-940 min). Nevertheless, the most striking result from our simulations is the fact that OpenLISEM did not predict overland flow generation at two out of the three locations where it was observed. Our simulations also showed that the forest roads are a source of the runoff generation and their configuration affects catchment connectivity.</p><p>At the outlet level, OpenLISEM achieved a satisfactory (0.50 < NSE ≤ 0.70) and very good (NSE > 0.80) model performance according to Moriasi, et al. (2015), in predicting total discharge (NSE=0.95), peak discharge (NSE=0.68), and the time of the peak (NSE=1.00), for the entire set of events under manual calibration. In addition, simulations in wet conditions achieved higher accuracy in comparison to the dry ones.</p><p>When using the parameterization based on the linear regression calibration, OpenLISEM simulation efficiency dropped, but still to satisfactory and very good (NSE<sub>overall</sub> = 0.58, NSE<sub>combined</sub> =0.86) accuracy levels for total discharge.</p><p>Overall, we conclude that calibrating post-fire hydrological response at catchment scale with the OpenLISEM model, can result in reliable simulations for total flow, peak discharge and timing of the peaks. When considering the parameterization of theta<sub>s</sub> as proxy for repellent and wettable soils, more information than the initial soil moisture is required.</p>

The hydrological cycle in a warmer world: combined effects of changes in snowmelt and evaporation on Rhine discharge evaluated with the new dS2 model

<p>Recent and projected changes in the climate are known to affect the hydrological cycle. Many studies have shown how these climate changes result in differences in for example, evaporation rates, melt of snow and ice, precipitation patterns and seasonality. Since these processes are influencing different parts of the hydrological cycle, the hydrological response as result of changes in climate can be rather complex (Buitink et al., 2019b). In this study, we investigate how the combined effects of changes in melt from frozen water and increased evaporation rates affect the hydrological response in the Rhine basin, using the new dS2 model (Buitink et al., 2019a). It is known that increased temperatures affect both the melt of frozen water and the energy available for evaporation. However, as temperatures will reach melting point earlier in the year, the contribution of meltwater to the total discharge will also peak earlier in the year. Contrary, evaporation will increase without strong changes in the seasonality. Since the Rhine depends for a significant fraction on meltwater from snow and ice during warm and dry summers, this change in timing can have significant impacts on the low flows. This study shows these effects both for the recent changes in climate, but also presents the sensitivity of the hydrological cycle to the changes in the climate.</p><p> </p><p>Buitink, J., Melsen, L. A., Kirchner, J. W., and Teuling, A. J.: A distributed simple dynamical systems approach (dS2 v1.0) for computationally efficient hydrological modelling, Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2019-150, in review, 2019a.</p><p>Buitink, J., Uijlenhoet, R., and Teuling, A. J.: Evaluating seasonal hydrological extremes in mesoscale (pre-)Alpine basins at coarse 0.5° and fine hyperresolution, Hydrol. Earth Syst. Sci., 23, 1593–1609, https://doi.org/10.5194/hess-23-1593-2019, 2019b.</p>

What is the contribution of snow and glacier to discharge in Swiss alpine headwater catchments under climate change?

<p><span>Switzerland is often referred to as Europe’s Water Tower. During the melt season, water stored in the Alps as snow and ice feeds large European rivers such as the Rivers Rhine and Rhone. Under climate change conditions, snow and glacier melt contributions to discharge are expected to change dramatically. These changes might be very important during dry periods, when snow and glacier melt are the main sources of water. Assessing water availability in the future is essential for sustainable management of our water resources. Understanding how much melt water contributes to the discharge at different locations along the rivers is therefore necessary. </span></p><p><span>In this study, we used a customized version of the bucket-type hydrological model HBV-light, specially developed to assess the daily contribution of snow and glacier melt to discharge in a transient way. We assess the discharge components for 195 glacierized headwater catchments covering the entire Swiss Alps from 1973 to 2099. Hydrological processes in the Alps are spatially and temporally highly variable. Snow and glacier melt modelling are also challenged by data scarcity. Heterogeneously distributed meteorological measurement stations in high elevated and remote regions further complicate the representativity of the data. We show the advantages and challenges of using datasets from various sources as meteorological input data and for model calibration and validation of discharge, snow and glacier cover. In a second step, we applied a regionalization approach to defining model parameters for the ungauged catchments. A multi-criteria calibration was used to ensure that all hydrological processes are correctly represented within the model. </span></p><p><span>For future climate projections, we used the newly generated precipitation and temperature gridded products from MeteoSwiss for 45 climate models and for three emissions scenarios (RCP 2.6, RCP 4.5 and RCP 8.5). The results show that glacier peak water is already reached by most of the catchments and will be reached by all catchments during the first half of the Century for all three emissions scenarios. Under RCP 8.5, total glacier contribution summarized over all headwater catchments is 8% of total discharge under current climate and less than 2% at the end of the century. Snow melt will still be an important contribution to discharge during the first half of the century. In the second half of the century, however, snow melt contribution will significantly decrease from 34% (current climate) to 25% +/- 10% (2070-2099) of the total discharge. In contrary, rainfall contribution will increase from 58% to 72% +/- 15% of total discharge. Overall, the total annual discharge is expected to decrease slightly. The intensity of these changes in discharge contributions depends on the catchment elevation and large regional differences can be observed. The effects are much smaller under emission scenario RCP 2.6. </span></p>