ASSESSING THE IMPACT OF URBANIZATION ON DIRECT RUNOFF IN DISTRICT 8, HO CHI MINH CITY

Ho Chi Minh City (HCMC) is among the cities that are most at risk of fl ooding worldwide. Urbanization processes have led to a change in land use, which in turn has resulted in an increase in impervious surfaces and runoff , thus again leading to the risk of fl ooding in the city. The aim of the article is to study the impact of urban development (on the example of District 8 of HCMC) on surface runoff using a combination of the interpretation of remote sensing images of the earth (ERS) Google Earth and the SCS-CN model (the Soil Conservation Service curve number). Theoretical models are used to analyze the relationship between the typology of buildings and areas of open and impervious surfaces. The interpretation of remote sensing images was carried out in the ArcGIS program. The method used to calculate surface runoff is the Soil Conservation Service Curve Number (SCS-CN) method developed by the US Soil Conservation Service and is suitable for assessing the eff ects of land-use/land cover change due to urbanization. The results of the study show the volume of surface runoff in areas with diff erent levels of urbanization in district 8 of HCMC, assessing the impact of urbanization processes on surface runoff and revealing new opportunities for managing this process. The combination of remote sensing interpretation and SCS-CN model makes it possible to assess the impact of urban development on surface runoff . Urbanization and an increase in built-up area strongly aff ect fl ooding, reducing the soil retention.

ANALISIS STATUS DAYA DUKUNG AIR DI SUB DAS CIKERUH MENGGUNAKAN METODE SOIL CONSERVATION CURVE NUMBER (SCS-CN)

Sub DAS Cikeruh merupakan kawasan dengan laju pertumbuhan penduduk yang tinggi, yang mana hal tersebut mengakibatkan alih fungsi lahan terjadi di beberapa kecamatan sehingga berimplikasi terhadap menurunnya ketersediaan air dan meningkatnya kebutuhan air di Sub DAS Cikeruh. Penelitian ini bertujuan untuk mengetahui status daya dukung air di Sub DAS Cikeruh melalui perbandingan rasio antara kebutuhan dan ketersediaan air. Kebutuhan air dihitung dengan menggunakan standar yang ditentukan oleh SNI 19-66728.1, 2002; SNI 67281-2015; dan Ditjen Cipta Karya Dinas PU tahun 1996, adapun sektor yang dihitung adalah domestik, non domestik, industri, pertanian, peternakan, dan perikanan. Ketersediaan air dihitung dengan mengestimasi volume aliran yang terjadi di Sub DAS Cikeruh menggunakan metode Soil Conservation Service Curve Number (SCS-CN) dari USDA dengan melibatkan data hidrologi dari tahun 2011 hingga 2020. Hasil penelitian menunjukkan bahwa ketersediaan air di Sub DAS Cikeruh pada tahun 2020 adalah sebesar 351.852.088,9 m3/tahun, sedangkan kebutuhan air di Sub DAS Cikeruh mengalami perubahan yang dinamis setiap tahunnya. Kebutuhan air di Sub DAS Cikeruh pada tahun 2011 adalah sebesar 545.250.212 m3/tahun, tahun 2015 sebesar 711.121.596 m3/tahun, sedangkan tahun 2020 sebesar 520.638.257 m3/tahun. Hasil perhitungan menunjukkan bahwa terjadi defisit air di Sub DAS Cikeruh, dimana nilai kebutuhan air lebih tinggi dibandingkan ketersediaan air, adapun rasionya sebesar 0,641, yang artinya daya dukung lingkungan telah terlampaui (overshoot) karena nilai rasio < 1.

Pemodelan Tutupan Lahan Untuk Menjamin Keberlanjutan Debit Sungai (Suatu Studi Di Sub DAS Cikapundung-Maribaya)

Changes in land use in the Cikapundung watershed, ie changes in forest land to built-up land, have an impact on the quantity of river water. Changes in land use in the Cikapundung River catchment are not ideal conditions for absorbing water. If land conversion is not controlled, it can have a large impact on reducing the availability of water resources for subordinate areas or what is called water scarcity. Analysis that takes into account land use and discharge can be done with several hydrological analysis methods, one of them is the Soil Conservation Service Curve Number (SCS-CN) method. Based on the calculation, the CN value was changed in 2014 from 57.275 to 62.591 where land cover changes began to occur. Keywords: land use, river water, water scarcity, hydrology, CN value

Adequacy of methodologies for determining SCS / CN in a watershed with characteristics of the Pampa biome

The Soil Conservation Service Curve Number Model is a conceptual model intended for estimating effective rainfall (ER). This model is grounded in a parameter – referred to as Curve Number (CN), which is determined from information on the characteristics of the watershed. The Standard Method (M1) for determining the CN is based on soil and land-use tables; however, some authors have proposed alternative methodologies for defining the CN value from monitored rainfall-runoff events, such as those described by Hawkins (1993) (M2), Soulis and Valiantzas (2012) (M3), and Soulis and Valiantzas (2013) (M4). The objective of this study was to evaluate the impact of using these methods for determination of the CN parameter on the estimation of ER, taking as reference forty rainfall-runoff events monitored between 2015 and 2018 in the Cadeia River Watershed, which has characteristics of the Pampa biome. The different methods assessed for definition of the CN parameter resulted in contrasting performances with respect to the estimation of ER for CRW, as the following findings: i) M1 gave ER values with little reliability, mainly due to the classification of antecedent moisture content classes; ii) M3 provided the best results in determining ER, followed by M2; and iii) the ER values estimated according to M4 differed from those observed, mainly for events with lower rainfall depths.

Delay minimization based uplink resource allocation for device-to-device communications considering mmWave propagation

This paper addresses the resource allocation problem in multi-sharing uplink for device-to-device (D2D) communication, one aspect of 5G communication networks. The main advantage and motivation in relation to the use of D2D communication is the significant improvement in the spectral efficiency of the system when exploiting the proximity of communication pairs and reusing idle resources of the network, mainly in the uplink mode, where there are more idle available resources. An approach is proposed for allocating resources to D2D and cellular user equipments (CUE) users in the uplink of a 5G based network which considers the estimation of delay bound value. The proposed algorithm considers minimization of total delay for users in the uplink and solves the problem by forming conflict graph and by finding the maximal weight independent set. For the user delay estimation, an approach is proposed that considers the multifractal traffic envelope process and service curve for the uplink. The performance of the algorithm is evaluated through computer simulations in comparison with those of other algorithms in the literature in terms of throughput, delay, fairness and computational complexity in a scenario with channel modeling that describes the propagation of millimeter waves at frequencies above 6 GHz. Simulation results show that the proposed allocation algorithm outperforms other algorithms in the literature, being highly efficient to 5G systems.