scholarly journals SIMULASI SUMUR RESAPAN BERDASARKAN ANALISIS PERBANDINGAN KETINGGIAN AIR BANJIR DI KELAPA GADING JAKARTA

2020 ◽  
Vol 3 (3) ◽  
pp. 797
Author(s):  
Lionel Felix ◽  
Gregorius Sandjaja Sentosa

Flooding has been a problem for the past few decades in Jakarta. The flooding in early January 2020 was one of the worst floods since 2013. One of the most severely affected areas was Kelapa Gading. To find a solution, infiltration wells are used. Infiltration well is a simple conservation in the form of a container that is built in the soil that functions to accommodate, hold and absorb surface water into the soil to increase the amount and position of the ground water level. The analysis begins by calculating the rainfall intensity from the January 2020 rainfall data, proceeding with the calculation of rainwater discharge with USSCS rational method, and calculation of the volume of water entering and not entering the drainage channel. This analysis focuses on flood water levels due to extreme rainfall, to then design infiltration wells. Analysis using the program is done after getting the results of manual calculations. The results of this analysis conclude that millions of infiltration wells are needed to absorb entire volume of flood water. This is due to the shallow groundwater and extreme conditions of rainfall.  Banjir sudah menjadi masalah selama beberapa dekade terakhir di Jakarta. Banjir pada awal Januari 2020 adalah salah satu banjir terparah sejak tahun 2013. Salah satu daerah yang paling terdampak adalah Kelapa Gading. Untuk mencari solusi banjir, digunakan sumur resapan. Sumur resapan adalah konservasi sederhana berupa wadah yang dibangun ke dalam tanah yang berfungsi menampung, menahan dan meresapkan air ke dalam tanah untuk meningkatkan muka air tanah. Analisis dimulai dengan menghitung intensitas hujan dari data curah hujan Januari 2020, lalu dilanjutkan dengan perhitungan debit air hujan dengan metode rasional USSCS, dan perhitungan volume air yang masuk dan tidak masuk ke saluran drainase. Analisis ini berfokus pada ketinggian air banjir akibat curah hujan yang ekstrim, untuk kemudian mendesain sumur resapan. Analisis menggunakan program dilakukan setelah mendapatkan hasil dari perhitungan manual. Hasil analisis ini menyimpulkan bahwa dibutuhkan jutaan sumur resapan untuk menyerap seluruh volume air banjir. Hal ini dikarenakan kondisi muka air tanah yang dangkal dan tingginya curah hujan.

2021 ◽  
Author(s):  
◽  
Craig Wayne Allen

<p>Te Hapua is a complex of small, privately owned wetlands approximately 60 km northwest of Wellington. The wetlands represent a large portion of the region's remaining palustrine swamps, which have been reduced to just 1% of the pre-1900 expanse. Whilst many land owners have opted to protect wetlands on their land with covenants, questions have been raised regarding potential threats stemming from the wider region. Firstly, some regional groundwater level records have shown significant decline in the 10 to 25 years they have been monitored. The reason for this is unclear. Wetlands are commonly associated with groundwater discharge, so a decline in groundwater level could adversely affect wetland water input. Secondly, estimated groundwater resources are currently just 8% allocated, so there is potential for a 92% increase in groundwater abstraction from aquifers that underlie the wetlands. Finally, predictions of future climate change indicate changes in rainfall quantity and intensity. This would likely alter the hydrological cycle, impacting on rainfall dependant ecosystems such as wetlands as well as groundwater recharge. Whilst previous ecological surveys at Te Hapua provide valuable information on biodiversity and ecological threat, there has been no detailed study of the hydrology of the wetlands. An understanding of the relationship between the surface water of the wetlands and the aquifers that underlie the area is important when considering the future viability of the wetlands. This study aims to define the local hydrology and assess the potential threat of 'long term' groundwater level decline, increased groundwater abstraction and predicted climate change. Eleven months of water level data was supplied by Wellington Regional Council for three newly constructed Te Hapua wetland surface water and adjacent shallow groundwater monitoring sites. The data were analysed in terms of their relative water levels and response to rainfall. A basic water balance was calculated using the data from the monitoring sites and a GIS analysis of elevation data mapped the wetlands and their watersheds. A survey of 21 individual wetlands was carried out to gather water quality and water regime data to enable an assessment of wetland class. Historical groundwater level trends and geological records were analysed in the context of potential threat to the wetlands posed by a decline in groundwater level. Climate change predictions for the Kapiti Coast were reviewed and discussed in the context of possible changes to the hydrological cycle and to wetlands. Results from the wetland survey indicated that there are two distinct bands of wetlands at Te Hapua. Fens are found mostly in the eastern band and are more likely to be discharge wetlands, some of which are ephemeral. Swamps are found mostly in the western band and are more likely to be recharge wetlands. Dominant water input to fens is via local rainfall and local through-flow of shallow groundwater, especially from surrounding dunes. The eastern band of wetlands is typified by higher dunes and hence has greater input from shallow groundwater than wetlands in the western band. Dominant water input to swamps is via local rainfall, runoff, and through-flow from the immediate watershed and adjacent wetlands. Overall, the future viability of the Te Hapua wetland complex appears promising. Historical groundwater declines appear to be minimal and show signs of reversing. Abstraction from deep aquifers is not likely to impact on wetland water levels. Climate change is likely to have an impact on the hydrological cycle and may increase pressure on some areas, especially ephemeral wetlands. The effect of climate change on groundwater level is more difficult to forecast, but may lower water level in the long term.</p>


2021 ◽  
Vol 882 (1) ◽  
pp. 012048
Author(s):  
M A Danasla ◽  
G J Kusuma ◽  
E J Tuheteru ◽  
R S Gautama

Abstract Analysis of water management in the pit lake is divided into two conditions, namely Continuous Events and Extreme Events. The former is an analysis of pit lake management related to the water filling in a pit lake that takes place continuously. Meanwhile, the later is the analysis of pit lake management related to the possibility of extreme conditions that will occur, including extreme rainfall. This study is focused only on the Extreme Event conditions. The Gumbel method is used to calculate the planned return period rainfall T concerning the prediction of extreme rainfall. Meanwhile, for a certain return period, rainfall intensity can be predicted using the Mononobe formula. Based on the result of calculation the Gumbel method, it shows that the planned rainfall for a return period of 10 years is 132.9 mm / day. Then based on the results of the calculation of rainfall intensity using the Mononobe formula, it is obtained that the intensity of rainfall for a return period of 10 years with a concentration-time of 5 minutes is 241.5 mm/hour, while the amount of rainfall intensity with a concentration-time of 300 minutes or 5 hours is 15.8 mm/hour.


2020 ◽  
Author(s):  
Mohamed Sultan ◽  
Karem Abdelmohsen ◽  
Himanshu Save

&lt;p&gt;Global warming is producing climatic changes across the world that affect in major ways the livelihood of major sectors of the world&amp;#8217;s population. Over the past decade or two, an increase in the frequency and intensity of specific climatic phenomena (e.g., hurricanes, wet or dry periods, etc.) has been reported from many parts of the globe and is believed to be climate change-related. Over the past few years, the largest and most intense precipitation events were recorded over the Tigris and Euphrates watershed (TEW), a heavily engineered watershed (&gt; 60 main dams) that is shared by Turkey, Iran, Syria, Saudi Arabia, and Iraq. Analysis of the Global Precipitation Climatology Project (GPCP) precipitation record over the past 40 year (1979-present) across the TEW revealed a prolonged dry period (2002- to 2017; Average Annual Precipitation [AAP]: 240 km&lt;sup&gt;3&lt;/sup&gt;), followed by wet years (2018 to 2020; AAP: 425 km&lt;sup&gt;3&lt;/sup&gt;). The recent extensive precipitation events during the wet period are reflected in GRACE and GRACE-FO data. Throughout the dry period there was a total decline in GRACE&lt;sub&gt;TWS&lt;/sub&gt; of 212 km&lt;sup&gt;3&lt;/sup&gt; (13.3 km&lt;sup&gt;3&lt;/sup&gt;/yr) followed by an increase of 246 km&lt;sup&gt;3&lt;/sup&gt; (82 km&lt;sup&gt;3&lt;/sup&gt;/yr) during the wet period.&amp;#160; In other words, in the past 2.5 years, the TEW more than recovered its losses during the previous 15 years. This recovery was enabled in part by the impoundment of surface water behind the many dams in the riparian countries and by infiltration of precipitation that recharged the TEW aquifers. Using radar altimetry we observe an increase in surface water levels by 8 m in Lake Ataturk, 13 m in Lake Karakaya, 1.5 m in Lake Van in Turkey, 5 m in Lake Assad in Syria, and 16 m in Lake Tharthar, and 24 m in Lake Mosul in Iraq.&amp;#160; These translate to a volume increase of 21.7 km&lt;sup&gt;3&lt;/sup&gt; in Turkey, 3.5 km&lt;sup&gt;3&lt;/sup&gt; in Syria, and 34 km&lt;sup&gt;3&lt;/sup&gt; in Iraq during the wet period. Using GRACE data and outputs of land surface models, we estimate that groundwater storage GRACE&lt;sub&gt;TWS&lt;/sub&gt; declined at a rate of -7 km&lt;sup&gt;3&lt;/sup&gt;/yr during the dry period and increased at a rate of 60 km&lt;sup&gt;3&lt;/sup&gt;/yr during the wet years.&lt;/p&gt;


Author(s):  
Henk van Hardeveld ◽  
Harm de Jong ◽  
Maxim Knepflé ◽  
Thijs de Lange ◽  
Paul Schot ◽  
...  

Abstract. To achieve a more sustainable management of the subsiding Dutch peatlands, adaptations such as progressively higher surface water levels, pressurized field drains and a transition from dairy farming to paludiculture are considered. However, a clear understanding of implementation pathways for adaptive management strategies is lacking. Therefore, we used the RE:PEAT tool to elucidate the short-term and long-term impacts during 2025–2100 of two adaptive management strategies in Polder Zegveld and how to fairly distribute the costs and benefits of these strategies among the stakeholder groups. The strategies resulted in marked differences in soil subsidence and temporal trends in societal costs and benefits that affected stakeholders unequally. The adaptations were shown to reduce soil subsidence and enhance the sustainability of peatland management. We explored several options for a collective implementation of the adaptative management strategies. In addition, we discuss several ideas to further capitalize on the potential of the RE:PEAT tool to support peatland management. Currently, we are developing additional features that enable high spatio-temporal resolution simulations of the integrated dynamics of the surface water system, the shallow groundwater system, rainfall-runoff processes and solute transport. In combination with the PCDitch model, this will also enable detailed ecological assessments. This will pave the way for implementation pathways for adaptive management strategies that will contribute to a more sustainable peatland management.


2021 ◽  
Author(s):  
◽  
Craig Wayne Allen

<p>Te Hapua is a complex of small, privately owned wetlands approximately 60 km northwest of Wellington. The wetlands represent a large portion of the region's remaining palustrine swamps, which have been reduced to just 1% of the pre-1900 expanse. Whilst many land owners have opted to protect wetlands on their land with covenants, questions have been raised regarding potential threats stemming from the wider region. Firstly, some regional groundwater level records have shown significant decline in the 10 to 25 years they have been monitored. The reason for this is unclear. Wetlands are commonly associated with groundwater discharge, so a decline in groundwater level could adversely affect wetland water input. Secondly, estimated groundwater resources are currently just 8% allocated, so there is potential for a 92% increase in groundwater abstraction from aquifers that underlie the wetlands. Finally, predictions of future climate change indicate changes in rainfall quantity and intensity. This would likely alter the hydrological cycle, impacting on rainfall dependant ecosystems such as wetlands as well as groundwater recharge. Whilst previous ecological surveys at Te Hapua provide valuable information on biodiversity and ecological threat, there has been no detailed study of the hydrology of the wetlands. An understanding of the relationship between the surface water of the wetlands and the aquifers that underlie the area is important when considering the future viability of the wetlands. This study aims to define the local hydrology and assess the potential threat of 'long term' groundwater level decline, increased groundwater abstraction and predicted climate change. Eleven months of water level data was supplied by Wellington Regional Council for three newly constructed Te Hapua wetland surface water and adjacent shallow groundwater monitoring sites. The data were analysed in terms of their relative water levels and response to rainfall. A basic water balance was calculated using the data from the monitoring sites and a GIS analysis of elevation data mapped the wetlands and their watersheds. A survey of 21 individual wetlands was carried out to gather water quality and water regime data to enable an assessment of wetland class. Historical groundwater level trends and geological records were analysed in the context of potential threat to the wetlands posed by a decline in groundwater level. Climate change predictions for the Kapiti Coast were reviewed and discussed in the context of possible changes to the hydrological cycle and to wetlands. Results from the wetland survey indicated that there are two distinct bands of wetlands at Te Hapua. Fens are found mostly in the eastern band and are more likely to be discharge wetlands, some of which are ephemeral. Swamps are found mostly in the western band and are more likely to be recharge wetlands. Dominant water input to fens is via local rainfall and local through-flow of shallow groundwater, especially from surrounding dunes. The eastern band of wetlands is typified by higher dunes and hence has greater input from shallow groundwater than wetlands in the western band. Dominant water input to swamps is via local rainfall, runoff, and through-flow from the immediate watershed and adjacent wetlands. Overall, the future viability of the Te Hapua wetland complex appears promising. Historical groundwater declines appear to be minimal and show signs of reversing. Abstraction from deep aquifers is not likely to impact on wetland water levels. Climate change is likely to have an impact on the hydrological cycle and may increase pressure on some areas, especially ephemeral wetlands. The effect of climate change on groundwater level is more difficult to forecast, but may lower water level in the long term.</p>


1988 ◽  
Vol 20 (3) ◽  
pp. 149-163 ◽  
Author(s):  
Carol Braester ◽  
Rudolf Martinell

Nearly one fifth of all water used in the world is obtained from groundwater. The protection of water has become a high priority goal. During the last decades pollution of water has become more and more severe. Today groundwater is more and more used in comparison with surface water. Recently we have seen accidents, which can pollute nearly all surface water very quickly. Generally the groundwater is easier to protect, as well as cheaper to purify, and above all it is of better quality than the surface water. During the past two decades, alternatives to the traditional method of treating the water in filters have been developed, that is in situ water treatment i.e. the VYREDOX and NITREDOX methods. The most common problem regarding groundwater is too high content of iron and manganese, which can be reduced with the VYREDOX method. In some areas today there are severe problems with pollution by hydrocarbons and nitrate as well, and with modification of the VYREDOX treatment method it is used for hydrocarbon and nitrate treatment as well. The method to reduce the nitrate and nitrite is known as the NITREDOX method.


Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 896
Author(s):  
Thanh Thu Nguyen ◽  
Makoto Nakatsugawa ◽  
Tomohito J. Yamada ◽  
Tsuyoshi Hoshino

This study aims to evaluate the change in flood inundation in the Chitose River basin (CRB), a tributary of the Ishikari River, considering the extreme rainfall impacts and topographic vulnerability. The changing impacts were assessed using a large-ensemble rainfall dataset with a high resolution of 5 km (d4PDF) as input data for the rainfall–runoff–inundation (RRI) model. Additionally, the prediction of time differences between the peak discharge in the Chitose River and peak water levels at the confluence point intersecting the Ishikari River were improved compared to the previous study. Results indicate that due to climatic changes, extreme river floods are expected to increase by 21–24% in the Ishikari River basin (IRB), while flood inundation is expected to be severe and higher in the CRB, with increases of 24.5, 46.5, and 13.8% for the inundation area, inundation volume, and peak inundation depth, respectively. Flood inundation is likely to occur in the CRB downstream area with a frequency of 90–100%. Additionally, the inundation duration is expected to increase by 5–10 h here. Moreover, the short time difference (0–10 h) is predicted to increase significantly in the CRB. This study provides useful information for policymakers to mitigate flood damage in vulnerable areas.


2016 ◽  
Vol 21 (3) ◽  
pp. 115-124 ◽  
Author(s):  
Naoyuki Yamashita ◽  
Hiroyuki Sase ◽  
Tsuyoshi Ohizumi ◽  
Junichi Kurokawa ◽  
Toshimasa Ohara ◽  
...  

2021 ◽  
Vol 13 (12) ◽  
pp. 6565
Author(s):  
Shama E. Haque

Phosphorus is an essential component of modern agriculture. Long-term land application of phosphorous-enriched fertilizers and animal manure leads to phosphorus accumulation in soil that may become susceptible to mobilization via erosion, surface runoff and subsurface leaching. Globally, highly water-soluble phosphorus fertilizers used in agriculture have contributed to eutrophication and hypoxia in surface waters. This paper provides an overview of the literature relevant to the advances in phosphorous management strategies and surface water quality problems in the U.S. Over the past several decades, significant advances have been made to control phosphorus discharge into surface water bodies of the U.S. However, the current use of phosphorus remains inefficient at various stages of its life cycle, and phosphorus continues to remain a widespread problem in many water bodies, including the Gulf of Mexico and Lake Erie. In particular, the Midwestern Corn Belt region of the U.S. is a hotspot of phosphorous fertilization that has resulted in a net positive soil phosphorous balance. The runoff of phosphorous has resulted in dense blooms of toxic, odor-causing phytoplankton that deteriorate water quality. In the past, considerable attention was focused on improving the water quality of freshwater bodies and estuaries by reducing inputs of phosphorus alone. However, new research suggests that strategies controlling the two main nutrients, phosphorus and nitrogen, are more effective in the management of eutrophication. There is no specific solution to solving phosphorus pollution of water resources; however, sustainable management of phosphorus requires an integrated approach combining at least a reduction in consumption levels, source management, more specific regime-based nutrient criteria, routine soil fertility evaluation and recommendations, transport management, as well as the development of extensive phosphorus recovery and recycling programs.


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