The Effects of Rain Intensity and Water Elevation with Energy Productivity of Kracak Hydro Power Plant, Bogor Regency – West Java

This paper was aimed to know the effects of rain intensity and water elevation with energy productivity of Kracak Hydro Power Plant, Bogor Regency – West Java. The method used multiple regression analysis with a quantitative approach to describe the effects of rain intensity and water elevation with energy productivity of Kracak Hydro Power Plant. Based on the data, the highest rain intensity was in February of 13,35 mm with water elevation of 346,09 cm and produced electrical energy of 198.296 kWh. The lowest rain intensity was in July of 0,86 mm with water elevation of 194,02 cm and produced electrical energy of 49.772 kWh. The average rain intensity was 8,9 mm with water elevation of 324,12 cm and produced electrical energy of 156.010 kWh. The results of testing the effect of rain intensity with energy productivity at the Kracak hydropower plant resulted in a significance value of 0.002 (p <0.05) and a t value of 4.306. This value indicates that the significance value is below 0.05 and has a positive coefficient direction. It means that rain intensity has a significant positive effect with energy productivity at the Kracak hydropower plant. And the results of testing the effect of water elevation with energy productivity at the Kracak hydropower plant resulted in a significance value of 0.003 (p <0.05) and a t value of 3.864. This value indicates that the significance value is below 0.05 and has a positive coefficient direction. It means that water elevation has a significant positive effect with energy productivity at the Kracak hydropower plant. The conclusion on this research is the rain intensity and water elevation have effects with energy productivity of Kracak Hydro Power Plant.

Measuring water waves in the field from bottom mounted pressure sensors

&lt;p&gt;For various experimental reasons, the measurement of water waves propagating in shallow water environments such as surf zones or coastal areas is a difficult task. Deploying surface measuring instruments can be inconvenient, dangerous, or simply expensive. Thus, such measurements are often performed using bottom mounted pressure sensors. Unfortunately, the problem of reconstructing surface elevation based on a single point pressure sensor is an ill-posed problem.&lt;/p&gt;&lt;p&gt;Indeed, the pressure data collected should be inverted to provide the related water elevation. However, the transfer function traditionally used to perform this inversion is subject to question. When considering very long waves, like tides and tsunamis, the pressure is hydrostatic as long as dispersive effects can be neglected and recovering surface elevation from the bottom pressure does not imply any particular difficulty. Yet, for steeper waves propagating in such depth conditions, nonlinearity might play a significant role (Didenkulova et al., 2021).&lt;/p&gt;&lt;p&gt;In coastal areas, the propagation of water waves is more complex, and often involves dispersion or nonlinearity. In such areas, one may find wind waves, which are strongly dispersive, even in the coastal zone. Using linear theory might be helpful, in such cases, but is also subject to questions (Touboul &amp; Pelinovsky, 2018). Besides, other corrections related to their dispersive behaviour might play a significant role. Various phenomena, such as partially standing waves (Touboul &amp; Pelinovsky, 2014), or the superimposition of current, might also play a significant role.&lt;/p&gt;&lt;p&gt;In this work, we investigate the performance of classical reconstruction techniques, but also more recent approaches (Oliveras et al., 2012, Clamond &amp; Constantin, 2013, Bonneton et al., 2018), by confronting their prediction to field data collected in the central part of the Bay of Biscay using current meters mounted with pressure and acoustic surface tracking sensors . These data are obtained in various depth conditions, often in extreme conditions and provide pressure records, current velocity, and direct measurement of the water elevation. Thus, the use of methods presenting various degrees of sophistication allows us to analyze in details the respective roles played by the current, the dispersion, and the nonlinearity.&lt;/p&gt;&lt;p&gt;The joint French-Russian grant No. 19-55-15005 is acknowledged.&lt;/p&gt;&lt;p&gt;[1] E. Didenkulova, E. Pelinovsky &amp; J. Touboul, Long-wave approximations in the description of bottom pressure, Wave Motion, vol. 100, No. 1, 102668 (2021)&lt;/p&gt;&lt;p&gt;[2] J. Touboul &amp; E. Pelinovsky, &quot;On the use of linear theory for measuring surface waves using bottom pressure distribution&quot;, Eur. J. Mech. B: Fluids, 67, 97&amp;#8211;103, (2018).&lt;/p&gt;&lt;p&gt;[3] J. Touboul &amp; E. Pelinovsky, &quot;Bottom pressure distribution under a solitonic wave reflecting on a vertical wall&quot;, Eur. J. Mech., B. Fluids, 48, p. 13-18, (2014).&lt;/p&gt;&lt;p&gt;[4] K.L. Oliveras, V. Vasan, B. Deconinck, D. Henderson, Recovering the water wave profile from pressure measurement, SIAM J. Appl. Math. 72 (3) 897&amp;#8211;918 (2012).&lt;/p&gt;&lt;p&gt;[5] P. Bonneton, D. Lannes, K. Martins., H. Michallet, A nonlinear weakly dispersive method for recovering the elevation of irrotational surface waves from pressure measurements, Coastal Engineering 138, 1&amp;#8211;8 (2018).&lt;/p&gt;&lt;p&gt;[6] D. Clamond, A. Constantin, Recovery of steady periodic wave profiles from pressure measurements at the bed, J. Fluid Mech. 714, 463&amp;#8211;475 (2013).&lt;/p&gt;

Effect of Varying Wind Intensity, Forward Speed, and Surface Pressure on Storm Surges of Hurricane Rita

Hurricane storm surges are influenced by several factors, including wind intensity, surface pressure, forward speed, size, angle of approach, ocean bottom depth and slope, shape and geographical features of the coastline. The relative influence of each factor may be amplified or abated by other factors that are acting at the time of the hurricane’s approach to the land. To understand the individual and combined influence of wind intensity, surface pressure and forward speed, a numerical experiment is conducted using Advanced CIRCulation + Simulating Waves Nearshore (ADCIRC + SWAN) by performing hindcasts of Hurricane Rita storm surges. The wind field generated by Ocean Weather Inc. (OWI) is used as the base meteorological forcing in ADCIRC + SWAN. All parameters are varied by certain percentages from those in the OWI wind field. Simulation results are analyzed for maximum wind intensity, wind vector pattern, minimum surface pressure, forward speed, maximum water elevation, station water elevation time series, and high water marks. The results for different cases are compared against each other, as well as with observed data. Changes in the wind intensity have the greatest impact, followed by the forward speed and surface pressure. The combined effects of the wind intensity and forward speed are noticeably different than their individual effects.

Hydroelectric

There are two methods for generating electricity from hydropower. The first, and by far the most common, is the use of flowing water to rotate a turbine, which then turns the generator shaft to generate electricity. For this type of “conventional” hydroelectric, there are two general approaches. The first is a storage dam, where water impoundment upstream of the dam is used to make a reservoir to store water, thus creating a vertical drop in water elevation and giving control over water flow. The second is a run-of-river scheme, such that a portion of a flowing river is diverted to generate electricity. The second method for generating electricity is called pumped storage. In this scheme, water is pumped from a lower to upper reservoir in order to store energy in the form of gravitational potential energy to be used later. In this respect, the system is operating as a battery to store energy for future use. The states of Washington, California, and Oregon control about half of the total US capacity.

Technical Evaluation and Boezem Bratang Operation Patterns In Surabaya

Surabaya is the second largest and most populous city in Indonesia and is inseparable from the problem of flooding which is still flooded the area of East Surabaya.Flooding is caused by Bratang boezem unable to accommodate rainwater discharge. Boeang Surabaya has an area of 19,900 m2, has two systems namely flood gates and flood pumps. The floodgate system will work to drain the boezem bratang water to wonokromo river if the water elevation at Wonokromo River is at under the elevation of Bratang boezem water and flow Gravitatively while the pump system will work if the floodgate system is no longer functioning. To overcome the problem of flooding in the region, it is necessary to conduct hydrological and hydraulics analysis by performing boezem routing to determine the Boezem capacity whether it can accept the planned rain discharge. a depth of 3 m is unable to accommodate a maximum flood discharge period of 2.5 and 10 years. so it is planned to increase the boezem depth which was originally 3 m to 4.6 m, and increase the pump capacity which was originally from 10.5 m3 / s to 14 m3 / s.From the plan, after the hydrologic and hydraulics analysis using Boezem routing, Boezem has been able to accommodate the planned rain discharge.

Assimilation of wide-swath altimetry water elevation anomalies to correct large-scale river routing model parameters

Land surface models combined with river routing models are widely used to study the continental part of the water cycle. They give global estimates of water flows and storages, but they are not without non-negligible uncertainties, among which inexact input parameters play a significant part. The incoming Surface Water and Ocean Topography (SWOT) satellite mission, with a launch scheduled for 2021 and with a required lifetime of at least 3 years, will be dedicated to the measuring of water surface elevations, widths and surface slopes of rivers wider than 100 m, at a global scale. SWOT will provide a significant number of new observations for river hydrology and maybe combined, through data assimilation, with global-scale models in order to correct their input parameters and reduce their associated uncertainty. Comparing simulated water depths with measured water surface elevations remains however a challenge and can introduce within the system large bias. A promising alternative for assimilating water surface elevations consists of assimilating water surface elevation anomalies which do not depend on a reference surface. The objective of this study is to present a data assimilation platform based on the asynchronous ensemble Kalman filter (AEnKF) that can assimilate synthetic SWOT observations of water depths and water elevation anomalies to correct the input parameters of a large-scale hydrologic model over a 21 d time window. The study is applied to the ISBA-CTRIP model over the Amazon basin and focuses on correcting the spatial distribution of the river Manning coefficients. The data assimilation algorithm, tested through a set of observing system simulation experiments (OSSEs), is able to retrieve the true value of the Manning coefficients within one assimilation cycle much of the time (basin-averaged Manning coefficient root mean square error, RMSEn, is reduced from 33 % to [1 %–10 %] after one assimilation cycle) and shows promising perspectives with assimilating water anomalies (basin-averaged Manning coefficient RMSEn is reduced from 33 % to [1 %–2 %] when assimilating water surface elevation anomalies over 1 year), which allows us to overcome the issue of unknown bathymetry.

A Numerical Study of Tsunami Generation by Horizontal Displacement of Sloping Seafloor

Tsunamis are generated primarily by the vertical displacement of the seafloor if the seafloor is flat. If the seafloor is slanted, the horizontal motion also contributes to the generation of tsunamis. A previous study proposed that such effects can be estimated by simply calculating the elevation of water due to the horizontal displacement of the slope. Two more studies later argued that the horizontal motion also results in horizontal momentum of the water, which amplifies the tsunami generation. In this study, we numerically simulate the tsunami generation process of flat and sloping seafloor. It is found that, for the flat seafloor, the initial water elevation equals the vertical seafloor displacement. For the sloping seafloor, the initial water elevation deviates from the vertical seafloor displacement, and the difference can be accurately evaluated by the horizontal seafloor displacement. Thus, the initial horizontal momentum of the water is negligible for tsunami generation.

Identifying social responses to inundation disasters: a humanity–nature interaction perspective

Non-technical abstract Through the global analysis of inundation disasters with regards to population and land elevation, we found that the largest number of people living in low-elevation land was in Asia. Population increase was also most rapid at these locations. Furthermore, through three case studies in Asia, we found that a critical land–water elevation difference was 1.5–2.0 m in relation to the prevention of disasters regarding groundwater and land as public goods, the protection of houses and buildings from tsunamis and the protection of temples from flooding.

Investigation of trapezoidal sharp-crested side weir discharge coefficients under subcritical flow regimes using CFD

Side weirs are utilized to regulate water surface and to control discharge and water elevation in rivers and channels. Here, the discharge coefficient for trapezoidal sharp-crested side weirs (TSCSW) and their affecting parameters are numerically investigated. To simulate the hydraulic and geometric characteristics of TSCSWs, three weir crest lengths of 15 cm, 20 cm and 30 cm with lengths of 20 cm, 30 cm and 40 cm and with two different sidewall slopes are utilized. The results show that for constant P/B (P: weir height, B: main channel width), the depth of flow along the channel and weir decreases as the crest length increases. Also, with increasing P/y1 ratio (P: weir height, y1: upstream flow depth), the discharge coefficient decreases for small crest lengths and increases for large crest lengths. The results show that for constant T/L ratio (T: passing flow width, L: side weir crest length), increasing the length, height and sidewall slope of a side weir will increase the discharge coefficient. It is observed that as the upstream Froude number increases for side weirs with longer crest lengths, the intensity of deviating flow and kinetic energy over the TSCSW will increase. Finally, some relations with high correlation factors are proposed for obtaining discharge coefficients using the dimensionless parameters of P/y1, T/L and Fr1. Based on proposed relations and sensitivity analysis, it is shown that T/L and P/y1 are the most effective parameters for reducing the discharge coefficient reduction.