Nugroho, LaksonoDjoko (2014) Model Hidrograf Satuan Sintetis pada Sungai Pasang Surut. Doctor thesis, Universitas Brawijaya.
Abstract
Tujuan penelitian ini mendapatkan Model hidrograf Satuan Sintetis Pada Sungai Pasang Surut. Lokasi penelitian di Daerah Aliran Sungai Gembong Kota/Kabupaten Pasuruan. Hidrograf Satuan Sintetis yang tidak dipengaruhi pasang surut menyebabkan perkiraan Hidrograf Banjir yang lebih rendah karena tidak memperhatikan pengaruh pasang surut. Beberapa peneliti telah menghasilkan Model-Model Hidrograf Satuan Sintetis (Model-Model HSS) yang tidak dipengaruhi oleh pasang surut, yaitu HSS Snyder (lokasi penelitian di USA, 1938), HSS Nakayasu (lokasi penelitian di Jepang, 1948), dan HSS Gama I (lokasi penelitian di Pulau Jawa, 1985), HSS Limantara (lokasi Penelitian Jawa, Bali, Kalimantan Timur, NTB, 2009). Kondisi ideal yang diharapkan adalah Hidrograf Satuan Sintetis yang dipengaruhi pasang surut sehingga didalam memperkirakan besarnya hidrograf banjir menjadi lebih baik dan aman. Metodenya adalah dari hidrograf satuan pengamatan yang diturunkan dari hidrograf satuan pengamatan pada AWLR Gembong-Warungdowo tahun 2008 -2011 dan ARR P3GI , Penentuan jarak pengaruh pasang surut dengan menentukan batas air segar ( Fresh Water ) , data topografi DAS, Pengamatan pasang surut di tiga titik pengamatan selama musim kemarau (Juli 2012), penghujan (Desember 2012, Januari 2013, Pebruari 2013, Penentuan tipe pasang surut di DAS Gembong dengan metode admiralty juga data pengamatan pasang surut di 4 stasiun pasang surut yaitu Pelabuhan Karang Kleta Timur Surabaya, Pelabuhan Surabaya, Karang Jamuang Barat, dan pelabuhan Kalianget Tahun 2007-2011, Pengukuran debit lateral inflow pada musim kemarau dan penghujan, Pengukuran kecepatan pada saat pasang tertinggi dan surut terendah di tiga titik pengamatan, dan dilakukan analisa statistik untuk mendapatkan Model HSS di tiga titik pengamatan tersebut yaitu PS1= 500 m dari muara), PS2 = 3.054 m dari muara dan PS3 = 6.135 m dari muara), data pengukuran trase memanjang melintang Sungai Gembong sepanjang 7.300 m, dilakukan verifikasi dan validasi dari hasil Model Persamaan yang didapatkan. Hasil penelitian ini menunjukkan : (1a). Debit puncak hidrograf banjir musim kemarau kecil karena hidrograf pengamatannya hanya terdiri dari base flow dan pengaruh pasang surut saja. (1b). Pada musim penghujan debit puncak hidrograf banjirnya besar karena terdiri dari baseflow , debit akibat hujan dan debit akibat pasang surut. (2) Parameter fisik yang berpengaruh terhadap model adalah luas DAS: A, panjang sungai utama: L, jarak titik berat DAS ke outlet: Lc, kemiringan sungai utama: S, dan koefisien kekasaran DAS: n. Model persamaan debit puncak Qp = (1.95 x 10 -16 ) .A 0.05 .L 0.70 .Lc 0.66 .S 0.22 .n -12.06 . (3) Parameter pasang surut yang berpengaruh terhadap debit puncak adalah adanya koefisien tampungan (K Laksono). (4). Model HSS Laksono- ErUb yang tidak dipengaruhi pasang surut adalah Q n = Qp {(t/Tp) 1.21 } dan Q t = Qp.e 0.130(Tp – t) dan h asil pengecekan penyimpangan Model Persamaan HSS Laksono- ErUb terhadap HSO yang tidak dipengaruhi pasang surut menunjukkan penyimpangannya kecil 0,219 % < 10 % Model HSS Laksono- ErUb tidal 2 yang dipengaruhi pasang surut adalah Q n = Qp + 6,255. (t/T p ), dan Q t = Qp.e 0,625(Tp – t) . Model HSS Laksono- ErUb tidal 1 Q n1 = Qp1 x [t/Tp1] 7 , Q t1 = Qp1.+ 1.113 (Tp1 – t), Q t2 = Q L x [t/T L ], Q n2 = Q L -14.40 (T L – t), Q n3 = Qp2 [t/Tp2] 30 , dan Q t3 = Qp2+ 8.80 (Tp2 – t). H asil pengecekan penyimpangan Model Persamaan HSS Laksono- ErUb tidal 2 terhadap HSO tidal 2 yang dipengaruhi pasang surut menunjukkan penyimpangannya kecil 5,286 % < 10 %, sedangkan h asil pengecekan penyimpangan Model Persamaan HSS Laksono- ErUb tidal 1 terhadap HSO tidal 1 yang dipengaruhi pasang surut menunjukkan penyimpangannya kecil 9,691 % < 10 %.
English Abstract
The purpose of this study is to get Synthetic Unit of Hydrograph Model in Tidal River. The research is located in Gembong Watershed, Pasuruan (both city and district). Synthetic Unit of Hydrograph which is not influenced by tides, caused lower Flood Hydrograph estimation because the influence of the tides is not considered. Some researches have produced Synthetic Unit Hydrograph models (SUH models) which is not influenced by tides, there are SUH Synder (research located in USA, 1938), SUH Nakayasu (research located in Japan, 1948), HSS Gama I (research located in Java, 1985), HSS Limantara (research located in Java, Bali, East Kalimantan, NTB, 2009). Expected ideal condition is a Synthetic Unit of Hydrograph model which is influenced by tides, so it will be better and safer while forecasting the amount of flood hydrograph. Method of this research is using observation of unit hydrograph which is derived from Unit Hydrograph of AWLR Gembong-Warungdowo 2008-2011 and ARR P3GI, determination of the distant effect of tides is by determining the border of fresh water, watershed topographic data, tidal observation at three observation points during dry season (July 2012) and rainy season (December 2012, January 2013, February 2013), determination of tidal type in Gembong Watershed using admiralty method and tidal observation data in 4 tidal station which is Karang Kleta Timur Surabaya Port, Surabaya Port, Karang Jamuang Barat, and Kalianget Port during 2007-2011, measurement of lateral inflow discharge during dry and rainy season, velocity measurement during the highest tide and the lowest tide at three observation points, and statistical analysis is performed to get SUH model at those three observation points, which is PS1=500m from springhead, PS2=3.054 m from springhead, and PS3=6.135 m from springhead, measurement data of transverse elongated trace Gembong River along 7.300 m, the result of Equation Models is verified and validated. Result shows: (1a) Flood Hydrograph peak discharge during dry season is small because the hydrograph observation only consist of base flow and tidal effect. (1b) Flood Hydrograph peak discharge during rainy season is big because it consists of base flow, discharge caused by rain, and discharge caused by tides. (2) Physical parameter that affects the model is the watershed area: A, main river length: L, the distance from watershed gravity to the outlet: Lc, the slope of the main river: S, and roughness coefficient of the watershed: n. Equation model of peak discharge is Qp = ( 1.95 x 10 -16 ) . A 0.05 .L 0.70 .Lc 0.66 .S 0.22 .n – 12.06 . (3) Tidal parameter which is effect the peak discharge is shown by Patch Coefficient (K Laksono). (4) SUH Model Laksono- ErUb which is not influenced by tides is Qn = { ( t / Tp ) 1.21 } and Qt = Qp.e 0.130 ( Tp - t ) and the result of irregularities check of equation model HSS Laksono- ErUB towards HSO which is not influenced by tides shows that the irregularities is small 0,219% < 10%. SUH model Laksono- ErUb tidal 2 which is influenced by tides is Qn = 6.255 . ( t / Tp ), and Qt = Qp.e 0 , 625 ( Tp - t ) .SUH model Laksono- ErUb tidal 1 Qn1 = Qp1 x [ t/Tp1 ] 7 , QT1 = Qp1 . + 1,113 ( TP1 - t ) , Qt2 = QL x [ t / TL ] , Qn2 = QL -14.40 ( N - t ) , Qn3 = Qp2 [ t/ TP2 ] 30 , and Qt3 = Qp2 + 8.80 ( TP2 - t ). Irregularities check of equation model SUH Laksono- ErUb tidal 2 towards HSO tidal 2 which is influenced by tides shows that the irregularities is small 5,826% < 10%, meanwhile irregularities check of equation model SUH Laksono- ErUb tidal 1 towards HSO tidal 1 which is influenced by tides shows that the irregularities is small 9,691% < 10%.
| Item Type: | Thesis (Doctor) |
|---|---|
| Identification Number: | DES/551.46/NUG/m/061405775 |
| Subjects: | 500 Natural sciences and mathematics > 551 Geology, hydrology, meteorology > 551.4 Geomorphology and hydrosphere |
| Divisions: | S2/S3 > Magister Teknik Elektro, Fakultas Teknik |
| Depositing User: | Endro Setyobudi |
| Date Deposited: | 10 Oct 2014 11:32 |
| Last Modified: | 10 Oct 2014 11:32 |
| URI: | http://repository.ub.ac.id/id/eprint/161016 |
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