scholarly journals Unsupervised learning approach in defining the similarity of catchments: Hydrological response unit based k-means clustering, a demonstration on Western Black Sea Region of Turkey

2020 ◽  
Vol 8 (3) ◽  
pp. 321-331 ◽  
Author(s):  
Ersin Aytaç
2010 ◽  
Vol 7 (1) ◽  
pp. 1167-1208 ◽  
Author(s):  
M. K. MacDonald ◽  
J. W. Pomeroy ◽  
A. Pietroniro

Abstract. Snow redistribution by wind and the resulting accumulation regimes were simulated for two winters over an alpine ridge transect located in the Canada Rocky Mountains. Simulations were performed using physically based blowing snow and snowmelt models. A hydrological response unit (HRU)-based spatial discretization was used rather than a more computationally expensive fully-distributed one. The HRUs were set up to follow an aerodynamic sequence, whereby eroded snow was transported from windswept, upwind HRUs to drift accumulating, downwind HRUs. HRUs were selected by examining snow accumulation patterns from manual snow depth measurements. Simulations were performed using two sets of wind speed forcing: (1) station observed wind speed, and (2) modelled wind speed from a widely applied empirical, terrain-based windflow model. Best results were obtained when using the site meteorological station wind speed data. The windflow model performed poorly when comparing the magnitude of modelled and observed wind speeds, though over-winter snow accumulation results obtained when using the modelled wind speeds were reasonable. However, there was a notable discrepancy (17%) between blowing snow sublimation quantities estimated when using the modelled and observed wind speeds. As a result, the end-of-winter snow accumulation was considerably underestimated (32%) when using the modelled wind speeds. That snow redistribution by wind can be adequately simulated in computationally efficient HRUs over this alpine ridge has important implications for representing snow transport in large-scale hydrology models and land surface schemes. Snow redistribution by wind was shown to significantly impact snow accumulation regimes in mountainous environments as snow accumulation was reduced to less than one-third of snowfall on windswept landscapes and nearly doubled in certain lee slope and treeline areas. Blowing snow sublimation losses were shown to be significant (approximately one-quarter of snowfall or greater).


2018 ◽  
Vol 13 (2) ◽  
pp. 83
Author(s):  
Santosa Sandy Putra ◽  
Soewarno Soewarno ◽  
Dwi Kristianto

Pengelolaan sedimentasi pada Daerah Aliran Sungai (DAS) Ciliwung hulu adalah salah satu kunci keberhasilan rencana pembangunan Waduk Ciawi. Sedimen yang dibawa oleh aliran sungai dapat ditampung menggunakan konstruksi mini sabodam. Kapasitas tampung yang kecil dari mini sabodam membuat struktur tersebut ramah lingkungan dan mudah dibangun. Namun demikian, letak dari mini sabodam perlu direncanakan agar dapat berfungsi secara maksimal (menampung sedimen yang akan masuk ke calon Waduk Ciawi). Penelitian ini bertujuan untuk memprediksi volume sedimen yang akan tertahan serta lokasi usulan pembangunan mini sabodam di DAS Ciliwung Hulu. Analisis potensi sedimen dilakukan dengan pemodelan numeris SWAT (Soil and Water Assessment Tool) dan didasarkan pada karakteristik tanah, kelerengan,  dan tutupan lahan yang ada. Kawasan DAS Ciliwung hulu diklasifikasikan ke dalam beberapa HRU (Hydrological Response Unit). Masing-masing HRU merepresentasikan respon kawasan tersebut terhadap kejadian hujan. Model yang telah divalidasi kemudian digunakan untuk mengukur laju sedimentasi pada lokasi usulan mini sabodam. Penelitian ini menghasilkan tata letak, kapasitas tampung minimum, dan pola pemeliharaan (pengerukan sedimen) yang harus dilakukan agar mini sabodam dapat terus berfungsi dengan baik. Hasil akhir penelitian ini merupakan rekomendasi penting bagi penyusunan rencana induk pengendalian sedimentasi Calon Waduk Ciawi.


Author(s):  
Inga GRINFELDE ◽  
Anda BAKUTE

The urbanised areas have a significant impact on hydrological processes of the catchment. The average annual urbanisation temp in EU is 0.6%. The existing version of conceptual hydrological model METQ is developed for natural hydrological response units such as forests, swamps and agricultural land. The growing urbanisation level force to add to the model urban hydrological response unit. This study aims to analyse local parameter sensitivity of urban hydrological response unit of conceptual hydrological model METQ. The local sensitivity was made using Monte-Carlo simulations. To evaluate local sensitivity Nash–Sutcliffe efficiency index (NSE), determination coefficient R2, percent bias (PBIAS), ratios the root mean square error to the standard deviation of measured data (RSR) in addition to the graphical method were used. The results show seven parameters to be calibrated the other 16 parameters have to stay as constant values for urban hydrological response unit.


Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1064 ◽  
Author(s):  
Zheng Wei ◽  
Baozhong Zhang ◽  
Yu Liu ◽  
Di Xu

As a well-built, distributed hydrological model, the Soil and Water Assessment Tool (SWAT) has rarely been evaluated at small spatial and short temporal scales. This study evaluated crop growth (specifically, the leaf area index and shoot dry matter) and daily evapotranspiration at the hydrological response unit (HRU) scale, and SWAT2009 was modified to accurately simulate crop growth processes and major hydrological processes. The parameters of the modified SWAT2009 model were calibrated using data on maize for seed from 5 HRUs and validated using data from 7 HRUs. The results show that daily evapotranspiration, shoot dry matter and leaf area index estimates from the modified SWAT2009 model were satisfactory at the HRU level, and the RMSE values associated with daily evapotranspiration, shoot dry matter, and leaf area index were reduced by 17.0%, 1.6%, and 71.2%, compared with SWAT2009. Thus, the influences of various optimal management practices on the hydrology of agricultural watersheds can be effectively assessed using the modified model.


2017 ◽  
Vol 31 (1) ◽  
pp. 46 ◽  
Author(s):  
Riki Rahmad ◽  
Ali Nurman

Penelitian ini bertujuan untuk melakukan simulasi model SWAT dalam menghitung besarnya laju erosi DAS, menguji kesesuaian model dalam memprediksi erosi, serta menentukan skenario penggunaan lahan yang paling optimal menurunkan laju erosi. Penelitian ini dilakukan di DAS Deli, Sumatera Utara. Pada penelitian ini analisis SWAT dilakukan dengan bantuan Sistem Informasi Geografi (SIG) melalui 4 proses yaitu delineasi, pembentukan Hydrological Response Unit (HRU), pengolahan data dan simulasi, serta proses visualisasi. Hasil penelitian menunjukkan besarnya erosi rata-rata DAS Deli adalah 410,72 ton/ha/tahun. Hasil ini menunjukkan DAS Deli termasuk kedalam Tingkat Bahaya Erosi (TBE) kategori Berat dengan kriteria sangat berat 37,04%, berat 17,07%, sedang 21,46%, ringan 17,38%, dan sangat ringan 7,04%. Uji validasi model menunjukkan bahwa ada hubungan positif antara debit model dan observasi dimana persentase perbedaan nilainya sangat kecil yang artinya besarnya debit model hampir sangat mendekati besarnya debit observasi, serta model dikategorikan sangat baik dalam melakukan simulasi debit aliran harian pada Sungai Deli. Metode skenario adalah berdasarkan analisis TBE. Hasil skenario penggunaan lahan berhasil menurunkan laju erosi DAS Deli 34,78% menjadi 267,88 ton/ha/tahun.This study aims to conduct SWAT model simulation calculation of the rate of erosion of the watershed, testing the suitability of the model in predicting erosion, land use scenarios and determine the most optimal decrease the rate of erosion. This research was conducted in the watershed Deli, North Sumatra. In this study, SWAT analysis performed with the help of Geographical Information Systems (GIS) through 4 delineation process, namely, the establishment of Hydrological Response Unit (HRU), data processing and simulation, as well as the visualization process. The results show the average amount of erosion DAS Deli is 410.72 ton/ha/year. These results indicate DAS Deli included into Erosion Hazard Level (TBE) weight category with very strict criteria 37.04%, 17.07% by weight, were 21.46%, 17.38% mild and very mild 7.04%. Test model validation indicates that there is a positive relationship between the discharge and observation models where the percentage difference in value is very small, which means the amount of discharge model is very very close to a number of discharge observations, and models are categorized very good at simulating the daily flow rate at the Deli River. The scenario method is based on analysis of TBE. The results of land use scenarios managed to reduce the rate of erosion of the watershed Deli 34.78% to 267.88 tons/ha/year.


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