tabel perhitungan evapotranspirasi potensial dengan metode penmann

Tabel Perhitungan Evapotranspirasi Potensial dengan Metode Penmann Modifikasi

NO. URAIAN LAMBANG SATUAN JAN FEB MAR APR MEI JUN JUL AGT SEPT OKT NOV DES

1 Temperatur t 27.03 27.07 27.50 27.30 27.73 27.14 26.92 26.79 26.93 27.01 27.05 27.03

2 Kelembaban Relatif RH % 81.00 79.75 78.83 79.92 80.50 81.75 80.58 77.25 78.00 78.08 78.83 79.83

3 Kecepatan Angin u km/jam 10.33 10.00 11.83 10.67 12.33 10.00 14.00 10.33 14.17 11.00 12.17 13.50

4 Penyinaran Matahari n/N % 23.00 22.25 21.53 22.58 21.62 22.85 22.60 22.88 21.87 22.35 22.67 22.27

5 Tekanan Uap Jenuh ea mbar 36.06 35.80 36.71 36.28 37.24 37.37 35.50 33.32 34.86 35.76 35.77 35.71

6 Tekanan Uap Nyata ed mbar 29.21 28.55 28.94 28.99 29.98 30.55 28.60 25.74 27.19 27.92 28.20 28.51

7 Fungsi Angin f(U) 2.681 2.603 3.030 2.758 3.147 2.603 3.536 2.681 3.575 2.836 3.108 3.419

8 W 0.765 0.766 0.770 0.768 0.772 0.766 0.764 0.763 0.764 0.765 0.766 0.765

9 Faktor Pembobotan 1 - W 1 - W 0.235 0.234 0.230 0.232 0.228 0.234 0.236 0.237 0.236 0.235 0.234 0.235

10 Radiasi Ekstra Tereksterial Ra mm/hari 14.87 15.34 15.39 14.95 14.12 1.92 13.72 14.44 15.07 15.22 14.86 14.67

11 Faktor Albedo r 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08

12 Radiasi Sinar Matahari Rs mm/hari 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37

13 Radiasi Gel Pendek Neto Rns mm/hari 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34

14 Fungsi Temperatur f(t) 16.107 16.113 16.200 16.160 16.247 16.128 16.085 16.058 16.087 16.102 16.150 16.105

15 Fungsi Tekanan Uap Nyata f(ed) 0.102 0.105 0.103 0.103 0.099 0.097 0.105 0.117 0.111 0.107 0.106 0.105

16 Fungsi Penyinaran Matahari f(n/N) 0.307 0.300 0.294 0.303 0.295 0.306 0.303 0.306 0.297 0.301 0.304 0.300

17 Radiasi Gelombang Netto Rnl mm/hari 0.505 0.507 0.492 0.505 0.474 0.477 0.511 0.574 0.528 0.521 0.522 0.508

18 Radiasi Netto Rn mm/hari -0.161 -0.167 -0.155 -0.163 -0.137 -0.134 -0.169 -0.230 -0.189 -0.180 -0.180 -0.168

19 Faktor Koreksi c 1.1 1.1 1.0 0.9 0.9 0.9 0.9 1.0 1.1 1.1 1.1 1.1

20 Evapotranspirasi Potensial Eto mm/hari 4.605 4.724 5.296 4.084 4.587 3.639 5.055 4.641 6.947 5.592 5.919 6.218

°C

Harga-harga ea, w, (1 - w), dan f(t) berdasarkan temperatur (t)

Suhu ea w (1 - w)f(t)

mbar

24.0 29.85 0.735 0.265 15.40

24.2 30.21 0.737 0.263 15.45

24.4 30.57 0.739 0.261 15.50

24.6 30.94 0.741 0.259 15.55

24.8 31.31 0.743 0.257 15.60

25.0 31.69 0.745 0.255 15.65

25.2 32.06 0.747 0.253 15.70

25.4 32.45 0.749 0.251 15.75

25.6 32.83 0.751 0.249 15.80

25.8 33.22 0.753 0.247 15.85

26.0 33.62 0.755 0.245 15.90

26.2 34.02 0.757 0.243 15.94

26.4 34.42 0.759 0.241 15.98

26.6 34.83 0.761 0.239 16.02

26.8 33.25 0.763 0.237 16.06

27.0 35.66 0.765 0.235 16.10

27.2 36.09 0.767 0.233 16.14

27.4 36.50 0.769 0.231 16.18

27.6 36.94 0.771 0.229 16.22

27.8 37.37 0.773 0.227 16.26

28.0 37.81 0.775 0.225 16.30

28.2 38.25 0.777 0.223 16.34

28.4 38.70 0.779 0.221 16.38

28.6 39.14 0.781 0.219 16.42

28.8 39.61 0.783 0.217 16.46

29.0 40.06 0.785 0.215 16.50

Sumber : Suhardjono, Ajar Mandiri, 1991

oC e1 (0 - 250 m)

Hubungan nilai Rs dengan Ra dan n/NRs = (0,25 + 0,54 n/N)

RaPersentase kecerahan matahari n/N (%)

20 30 40 50 60 70 80 90

12.0 4.3 4.9 5.6 6.2 6.9 7.5 8.2 8.8

12.2 4.4 5.0 5.7 6.3 7.0 7.7 8.3 9.0

12.4 4.4 5.1 5.8 6.4 7.1 7.8 8.5 9.1

12.6 4.5 5.2 5.9 6.6 7.2 7.9 8.6 9.3

12.8 4.6 5.3 6.0 6.7 7.3 8.0 8.7 9.4

13.0 4.7 5.4 6.1 6.8 7.5 8.2 8.9 9.6

13.2 4.7 5.4 6.2 6.9 7.6 8.3 9.0 9.7

13.4 4.8 5.5 6.2 7.0 7.7 8.4 9.1 9.9

13.6 4.9 5.6 6.3 7.1 7.8 8.5 9.3 10.0

13.8 4.9 5.7 6.4 7.2 7.9 8.7 9.4 10.2

14.0 5.0 5.8 6.5 7.3 8.0 8.8 9.5 10.3

14.2 5.1 5.9 6.6 7.4 8.2 8.9 9.7 10.5

14.4 5.2 5.9 6.7 7.5 8.3 9.0 9.8 10.6

14.6 5.2 6.0 6.8 7.6 8.4 9.2 10.0 10.7

14.8 5.3 6.1 6.9 7.7 8.5 9.3 10.1 10.9

15.0 5.4 6.2 7.0 7.8 8.6 9.4 10.2 11.0

15.2 5.4 6.3 7.1 7.9 8.7 9.5 10.4 11.2

15.4 5.5 6.3 7.2 8.0 8.8 9.7 10.5 11.3

15.6 5.6 6.4 7.3 8.1 9.0 9.8 10.6 11.5

15.8 5.7 6.5 7.4 8.2 9.1 9.9 10.8 11.6

16.0 5.7 6.6 7.5 8.3 9.2 10 10.9 11.8

16.2 5.8 6.7 7.5 8.4 9.3 10.2 11.0 11.9

Min 4.3 4.9 5.6 6.2 6.9 7.5 8.2 8.8

Max 5.8 6.7 7.5 8.4 9.3 10.2 11.0 11.9

Rerata 5.1 5.8 6.6 7.3 8.1 8.9 9.6 10.4

Sumber : Suhardjono, 1989 : 45

Hubungan antara (ea) dan (ed) untuk berbagai keadaan (RH) dalam penggunaan rumus Penman

ea Harga ed = ea * RH

m.bar 55 60 65 70 75 80 85

29.50 16.23 17.70 19.18 20.65 22.13 23.60 25.07

29.75 16.36 17.85 19.34 20.82 22.31 23.80 25.29

30.00 16.50 18.00 19.50 21.00 22.50 24.00 25.50

30.25 16.64 18.15 19.66 21.18 22.69 24.20 25.71

30.50 16.77 18.30 19.82 21.35 22.88 24.40 25.93

30.75 16.91 18.45 19.99 21.52 23.06 24.60 26.14

31.00 17.05 18.60 20.15 21.70 23.25 24.80 26.35

31.25 17.19 18.75 20.31 21.88 23.44 25.00 26.56

31.50 17.32 18.90 20.48 22.05 23.63 25.20 26.77

31.75 17.46 19.05 20.64 22.23 23.81 25.40 26.99

32.00 17.60 19.20 20.80 22.40 24.00 25.60 27.20

32.25 17.74 19.35 20.96 22.57 24.19 25.80 27.41

32.50 17.88 19.50 21.13 22.75 24.38 26.00 24.63

32.75 18.01 19.65 21.29 22.93 24.56 26.20 27.84

33.00 18.15 19.80 21.45 23.10 24.75 26.40 28.05

33.25 18.29 19.95 21.61 23.27 24.94 26.60 28.26

33.50 18.43 20.10 21.44 23.45 25.13 26.80 28.48

33.75 18.56 20.25 21.94 23.63 25.31 27.00 28.69

34.00 18.70 20.40 22.10 23.80 25.50 27.20 28.90

34.25 18.84 20.55 22.25 23.98 25.69 27.40 29.11

34.50 18.98 20.70 22.43 24.15 25.88 27.60 29.32

34.75 19.11 20.85 22.59 24.32 26.06 27.80 29.54

35.00 19.25 21.00 22.75 24.50 26.25 28.00 29.75

35.25 19.39 21.15 22.91 24.68 26.44 28.20 29.96

35.50 19.52 21.30 23.07 24.85 26.63 28.40 30.18

35.75 19.66 21.45 23.24 25.02 26.81 28.60 30.39

36.00 19.80 21.60 23.40 25.20 27.00 28.80 30.60

36.25 19.94 21.75 23.56 25.38 27.19 29.00 30.81

36.50 20.07 21.90 23.73 25.55 27.38 29.20 31.02

36.75 20.21 22.05 23.89 25.73 27.56 29.40 31.24


Harga f(ed) guna perhitungan rumus Penmann

ed f(ed) = 0,34 - 0,044 (ed)^0,5

m.bar ,0 ,25 ,5 ,75

15 0.170 0.168 0.167 0.165

16 0.164 0.163 0.161 0.160

17 0.159 0.157 0.156 0.155

18 0.153 0.152 0.151 0.149

19 0.148 0.147 0.146 0.144

20 0.143 0.142 0.141 0.140

21 0.138 0.137 0.136 0.135

22 0.134 0.132 0.131 0.130

23 0.129 0.128 0.127 0.126

24 0.124 0.123 0.122 0.121

25 0.120 0.119 0.118 0.117

26 0.116 0.115 0.113 0.112

27 0.111 0.110 0.109 0.108

28 0.107 0.106 0.105 0.104

29 0.103 0.102 0.101 0.100

30 0.099 0.098 0.097 0.096

31 0.095 0.094 0.093 0.092

32 0.091 0.090 0.089 0.088

33 0.087 0.086 0.085 0.840

34 0.083 0.082 0.082 0.081

35 0.080 0.079 0.078 0.077

36 0.076 0.075 0.074 0.073


Harga f(n/N) guna perhitungan rumus Penmann

n/N f(n/N) = 0,1 + 0,9 n/N

(%) ,0 ,2 ,4 ,6 ,8

30 0.370 0.388 0.406 0.424 0.442

40 0.460 0.478 0.496 0.514 0.532

50 0.550 0.568 0.586 0.604 0.622

60 0.640 0.658 0.676 0.694 0.712

70 0.730 0.748 0.766 0.784 0.802

80 0.820 0.838 0.856 0.874 0.892

Sumber : Suhardjono,1989 : 47

Harga f(u) guna perhitungan rumus Penmann

u f(u) = 0,27 (1 + u x 0,864)

(m/dt) ,0 ,2 ,4 ,6 ,8

0 0.270 0.317 0.363 0.410 0.457

1 0.503 0.550 0.597 0.643 0.690

2 0.737 0.783 0.830 0.877 0.923

3 0.970 1.016 1.063 1.110 1.156

4 1.203 1.250 1.296 1.343 1.390


Besar angka koefisien bulanan (c) untuk rumus Penmann

Bulan c Bulan c

Januari 1.1 Juli 0.9

Februari 1.1 Agustus 1.0

Maret 1.0 September 1.1

April 0.9 Oktober 1.1

Mei 0.9 November 1.1

Juni 0.9 Desember 1.1


Tabel Rangking Tahunan Curah Hujan Harian

Bulan Januari Bulan Februari Bulan Maret Bulan April

JCHH (mm/hari) Tahun JCHH (mm/hari) Tahun JCHH (mm/hari) Tahun JCHH (mm/hari) Tahun202.5 1993 152.3 1995 228.5 1994 210.7 1994170 1994 85.5 1994 208.4 1995 210 1995109 1995 37.2 1990 175.5 1993 159.5 199062.2 1991 29.5 1993 112.4 1991 129 199362.2 1992 20.4 1991 112.4 1992 102 199159.5 1990 20.4 1992 58 1990 102 1992

Bulan Mei Bulan Juni Bulan Juli Bulan Agustus

JCHH (mm/hari) Tahun JCHH (mm/hari) Tahun JCHH (mm/hari) Tahun JCHH (mm/hari) Tahun346.5 1994 133 1994 225.8 1990 165.5 1994254.5 1995 132.5 1995 135.5 1995 163 1991252 1993 129.5 1991 132.5 1991 158 1992

148.3 1991 129.5 1992 132.5 1992 126 1995148.3 1992 98 1993 108.5 1993 86 1990102.5 1990 28.3 1990 68.5 1994 1993

Bulan September Bulan Oktober Bulan November Bulan Desember

JCHH (mm/hari) Tahun JCHH (mm/hari) Tahun JCHH (mm/hari) Tahun JCHH (mm/hari) Tahun283.4 1990 431.8 1990 316 1990 239 1991191.5 1992 284.5 1993 297 1994 234 1992191 1991 278.5 1995 294 1993 217 1993

148.8 1995 131 1994 294 1995 175 1995134.5 1994 94.2 1991 209.5 1991 169 1990129.1 1993 94.2 1992 209.5 1992 60.5 1994

Tabel 3.3. Curah Hujan Efektif untuk Tanaman Padi

Bulan Jan Feb Mar Apr Mei Jun

15 harian I II I II I II I II I II I II

19.00 151.00 61.00 24.50 143.50 64.90 105.00 105.00 136.00 118.50 69.00 63.50

13.30 105.70 42.70 17.15 100.45 45.43 73.50 73.50 95.20 82.95 48.30 44.45

0.89 7.05 2.85 1.14 6.70 3.03 4.90 4.90 6.35 5.53 3.22 2.96

3.97 1.99 4.86 4.90 5.94 3.09

Bulan Jul Agt Sept Okt Nov Des


67.00 68.50 50.00 113.00 104.00 87.50 88.00 196.50 112.50 184.50 63.50 170.50

46.90 47.95 35.00 79.10 72.80 61.25 61.60 137.55 78.75 129.15 44.45 119.35

3.13 3.20 2.33 5.27 4.85 4.08 4.11 9.17 5.25 8.61 2.96 7.96

3.16 3.80 4.47 6.64 6.93 5.46

Tabel 3.4. Curah Hujan Efektif untuk Tanaman Palawija

Bulan Jan Feb Mar Apr Mei Jun


66.00 43.00 15.00 22.20 146.50 29.00 79.00 80.50 172.50 79.50 95.00 34.50

46.20 30.10 10.50 15.54 102.55 20.30 55.30 56.35 120.75 55.65 66.50 24.15

3.08 2.01 0.70 1.04 6.84 1.35 3.69 3.76 8.05 3.71 4.43 1.61

2.54 0.87 4.10 3.72 5.88 3.02

Bulan Jul Agt Sept Okt Nov Des


66.00 66.50 45.00 113.00 103.50 87.50 63.00 215.50 200.00 94.00 77.00 140.00

46.20 46.55 31.50 79.10 72.45 61.25 44.10 150.85 140.00 65.80 53.90 98.00

3.08 3.10 2.10 5.27 4.83 4.08 2.94 10.06 9.33 4.39 3.59 6.53

3.09 3.69 4.46 6.50 6.86 5.06

R80 (mm/hari)

Re (mm/15 hari)

Re (mm/ hari)

R80 (mm/hari)

Re (mm/15 hari)

Re (mm/ hari)

R80 (mm/hari)

Re (mm/15 hari)

Re (mm/ hari)

R80 (mm/hari)

Re (mm/15 hari)

Re (mm/ hari)

Data : Temperatur Maksimum

TahunBulan

Jan Feb Mar Apr Mei Jun Jul Agt Sept Okt Nov Des

1992 31.60 31.90 32.10 32.20 31.90 31.70 31.60 33.10 32.30 32.80 31.50 31.20

1993 30.70 33.00 33.20 31.60 31.70 32.40 30.80 31.30 31.90 31.80 31.40 31.80

1994 31.90 31.80 31.70 32.40 31.90 33.30 31.20 30.60 31.90 33.50 32.10 30.90

1995 32.60 31.80 31.10 32.70 32.20 31.30 31.40 31.50 32.90 32.50 31.70 31.60

1996 31.00 31.70 32.10 32.20 32.30 31.70 31.40 32.20 32.50 31.20 32.40 31.60

1997 31.40 30.80 32.10 32.10 33.00 31.90 31.30 32.40 31.80 31.80 32.60 32.50

Min 30.70 30.80 31.10 31.60 31.70 31.30 30.80 30.60 31.80 31.20 31.40 30.90

Max 32.60 33.00 33.20 32.70 33.00 33.30 31.60 33.10 32.90 33.50 32.60 32.50

Rerata 31.53 31.83 32.05 32.20 32.17 32.05 31.28 31.85 32.22 32.27 31.95 31.60

Data : Temperatur Minimum

TahunBulan


1992 22.80 21.20 21.40 21.50 22.40 22.10 21.90 21.10 22.10 21.80 22.60 23.00

1993 20.00 22.50 22.80 22.80 22.80 21.40 21.70 21.90 20.40 22.10 20.90 22.00

1994 22.80 22.70 23.70 22.30 23.00 22.10 22.80 20.90 20.60 20.70 22.10 22.00

1995 22.00 23.20 22.90 22.90 23.40 22.60 23.00 22.10 21.40 21.30 22.90 22.60

1996 22.60 21.80 24.30 22.50 23.50 22.60 24.50 21.40 22.00 22.20 22.00 22.90

1997 25.00 22.40 22.60 22.40 24.70 22.60 21.50 23.00 23.40 22.40 22.40 22.20

Min 20.00 21.20 21.40 21.50 22.40 21.40 21.50 20.90 20.40 20.70 20.90 22.00

Max 25.00 23.20 24.30 22.90 24.70 22.60 24.50 23.00 23.40 22.40 22.90 23.00

Rerata 22.53 22.30 22.95 22.40 23.30 22.23 22.57 21.73 21.65 21.75 22.15 22.45

Data : Perhitungan Temperatur Rata-rata

Bulan Jan Feb Mar Apr Mei Jun Jul Agt Sept Okt Nov Des

Min 22.53 22.30 22.95 22.40 23.30 22.23 22.57 21.73 21.65 21.75 22.15 22.45

Max 31.53 31.83 32.05 32.20 32.17 32.05 31.28 31.85 32.22 32.27 31.95 31.60

Rerata 27.03 27.07 27.50 27.30 27.73 27.14 26.92 26.79 26.93 27.01 27.05 27.03

Data : Rata-rata Penyinaran Matahari

TahunBulan


1992 22.20 23.00 22.30 22.40 21.10 22.60 21.70 22.30 20.60 22.20 22.80 21.70

1993 24.00 22.60 22.50 23.20 21.00 22.60 22.70 22.90 22.60 23.10 22.00 22.70

1994 23.00 20.90 21.30 22.70 21.80 22.60 22.40 22.50 21.70 22.30 22.90 22.40

1995 23.20 22.10 22.10 23.20 22.20 23.70 22.40 22.40 22.60 22.30 22.40 22.80

1996 22.60 22.90 20.40 22.20 21.90 22.60 23.00 23.80 21.20 21.40 22.10 22.00

1997 23.00 22.00 20.60 21.80 21.70 23.00 23.40 23.40 22.50 22.80 23.80 22.00

Min 22.20 20.90 20.40 21.80 21.00 22.60 21.70 22.30 20.60 21.40 22.00 21.70

Max 24.00 23.00 22.50 23.20 22.20 23.70 23.40 23.80 22.60 23.10 23.80 22.80

Rerata 23.00 22.25 21.53 22.58 21.62 22.85 22.60 22.88 21.87 22.35 22.67 22.27

Data : Rata-Rata Kecepatan Angin (km/jam)

TahunBulan


1992 15.00 11.00 13.00 15.00 15.00 8.00 12.00 12.00 8.00 12.00 11.00 20.00

1993 10.00 10.00 15.00 10.00 13.00 12.00 20.00 12.00 10.00 10.00 12.00 15.00

1994 8.00 15.00 15.00 8.00 12.00 8.00 29.00 10.00 12.00 12.00 13.00 10.00

1995 8.00 5.00 11.00 8.00 8.00 8.00 6.00 8.00 20.00 10.00 12.00 9.00

1996 13.00 10.00 8.00 15.00 17.00 9.00 8.00 8.00 29.00 12.00 8.00 9.00

1997 8.00 9.00 9.00 8.00 9.00 15.00 9.00 12.00 6.00 10.00 17.00 18.00

Min 8.00 5.00 8.00 8.00 8.00 8.00 6.00 8.00 6.00 10.00 8.00 9.00

Max 15.00 15.00 15.00 15.00 17.00 15.00 29.00 12.00 29.00 12.00 17.00 20.00

Rerata 10.33 10.00 11.83 10.67 12.33 10.00 14.00 10.33 14.17 11.00 12.17 13.50

Rerata 2.8704 2.7778 3.287 2.963 3.4259 2.7778 3.8889 2.8704 3.9352 3.0556 3.3796 3.75

Data : Kelembaban Minimum

TahunBulan


1992 68.00 64.00 64.00 63.00 66.00 66.00 60.00 56.00 60.00 65.00 66.00 64.00

1993 60.00 62.00 50.00 69.00 63.00 69.00 65.00 57.00 56.00 60.00 63.00 72.00

1994 67.00 57.00 65.00 59.00 64.00 69.00 68.00 66.00 62.00 53.00 65.00 68.00

1995 66.00 67.00 67.00 64.00 68.00 63.00 68.00 66.00 59.00 66.00 60.00 61.00

1996 67.00 64.00 60.00 64.00 64.00 66.00 61.00 43.00 64.00 56.00 58.00 65.00

1997 65.00 64.00 62.00 63.00 65.00 67.00 65.00 64.00 65.00 62.00 57.00 54.00

Min 60.00 57.00 50.00 59.00 63.00 63.00 60.00 43.00 56.00 53.00 57.00 54.00

Max 68.00 67.00 67.00 69.00 68.00 69.00 68.00 66.00 65.00 66.00 66.00 72.00

Rerata 65.50 63.00 61.33 63.67 65.00 66.67 64.50 58.67 61.00 60.33 61.50 64.00

Data : Kelembaban Maksimum

TahunBulan


1992 97.00 97.00 97.00 96.00 96.00 97.00 96.00 96.00 95.00 97.00 96.00 97.00

1993 97.00 96.00 96.00 98.00 96.00 97.00 97.00 98.00 93.00 97.00 95.00 95.00

1994 96.00 96.00 97.00 97.00 96.00 96.00 97.00 94.00 95.00 97.00 97.00 96.00

1995 96.00 97.00 95.00 96.00 95.00 97.00 97.00 97.00 96.00 94.00 98.00 96.00

1996 97.00 98.00 96.00 96.00 96.00 97.00 97.00 97.00 95.00 93.00 95.00 95.00

1997 96.00 95.00 97.00 94.00 97.00 97.00 96.00 93.00 96.00 97.00 96.00 95.00

Min 96.00 95.00 95.00 94.00 95.00 96.00 96.00 93.00 93.00 93.00 95.00 95.00

Max 97.00 98.00 97.00 98.00 97.00 97.00 97.00 98.00 96.00 97.00 98.00 97.00

Rerata 96.50 96.50 96.33 96.17 96.00 96.83 96.67 95.83 95.00 95.83 96.17 95.67

Data : Kelembaban Relatif (%)

Bulan Jan Feb Mar Apr Mei Jun Jul Agt Sept Okt Nov Des

Min 65.50 63.00 61.33 63.67 65.00 66.67 64.50 58.67 61.00 60.33 61.50 64.00

Max 96.50 96.50 96.33 96.17 96.00 96.83 96.67 95.83 95.00 95.83 96.17 95.67

Rerata 81.00 79.75 78.83 79.92 80.50 81.75 80.58 77.25 78.00 78.08 78.83 79.83

Tabel Kebutuhan Air Selama Penyiapan Lahan

Eo + P T = 30 hari T = 45 hari

mm/hari S = 250 mm S = 300 mm S = 250 mm S = 300 mm

5.0 11.1 12.7 8.4 9.5

5.5 11.4 13.0 8.8 9.8

6.0 1.7 13.3 9.1 10.1

6.5 12.0 13.6 9.4 10.4

7.0 12.3 13.9 9.8 10.8

7.5 12.6 14.2 10.1 11.1

8.0 13.0 14.5 10.5 11.4

8.5 13.3 14.8 10.8 11.8

9.0 13.6 15.2 11.2 12.1

9.5 14.0 15.5 11.6 12.5

10.0 14.3 15.8 12.0 12.9

10.5 14.7 16.2 12.4 13.2

11.0 15.0 16.5 12.8 13.6

Tabel Perhitungan Kebutuhan Air Untuk Pola Tanam Padi - Padi - Palawija Tabel Kebutuhan Air Selama Penyiapan Lahan

No.Bulan

SatuanJul Agt Sept Okt Nov Des Jan Feb Mar Apr Mei Jun

Periode 15 harian ke- I II I II I II I II I II I II I II I II I II I II I II I II

1 Pola Tanam mm/hrPenyiapan

Padi I Penyiapan

Padi II PalawijaLahan Lahan

2 Evapotranspirasi potensial (Eto) mm/hr 5.58 5.58 5.00 5.00 5.50 5.50 5.73 5.73 5.20 5.20 5.35 5.35 5.70 5.70 5.26 5.26 6.08 6.08 5.41 5.41 5.37 5.37 5.09 5.09

3 Koefisien Tanaman (Kc)

LP 1.10 1.10 1.05 1.05 0.95 0.00 LP 1.10 1.10 1.05 1.05 0.95 0.00 0.50 0.75 1.00 1.00 0.82 0.45 LP

LP LP 1.10 1.10 1.05 1.05 0.95 0.00 LP LP 1.10 1.10 1.05 1.05 0.95 0.00 0.50 0.75 1.00 1.00 0.82 0.45

d. Kc LP LP 1.10 1.08 1.05 1.00 0.48 0.00 LP LP 1.10 1.08 1.05 1.00 0.48 0.25 0.63 0.88 1.00 0.91 0.64 LP

4 Curah Hujan Efektif (Re) mm/hr 2.31 0.00 0.93 1.96 2.36 3.24 3.85 1.61 3.64 6.88 5.09 3.55 4.41 4.32 3.36 1.70 0.00 7.30 5.58 4.95 6.25 3.17 4.62 3.71

5 Perkolasi (P) mm/hr 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00

6 Penggantian Lapisan Air (WLR) mm/hr 2.20 2.20 1.10 1.10 2.20 2.20 1.10 1.10

7 M = Eo + P 7.50 7.50 8.05 8.05 8.30 8.30 7.72 7.72 7.89 7.89 8.27 8.27 7.79 7.79 8.69 8.69 7.95 7.95 7.91 7.91 7.60 7.60

8 Keb. Air Tanaman (Etc) mm/hr 12.60 12.60 6.05 5.91 6.02 5.73 2.47 0.00 12.91 12.91 6.27 6.13 5.52 5.26 2.89 1.52 3.38 4.73 5.37 4.89 3.23 12.68

9 Kebutuhan Air Bersih di sawah (NFR) mm/hr 11.67 10.64 7.89 6.87 5.27 7.22 0.00 0.00 7.82 9.36 6.06 6.01 5.26 6.66 2.89 0.00 0.00 0.00 0.00 1.71 0.00 8.97

10 NFR = NFR/8,64 lt/dt/ha 1.35 1.23 0.91 0.80 0.61 0.84 0.00 0.00 0.91 1.08 0.70 0.70 0.61 0.77 0.33 0.00 0.00 0.00 0.00 0.20 0.00 1.04

Sumber : Hasil Perhitungan

Keterangan :

2.31 0.00 0.93 1.96 2.36 3.24 3.85 1.61 3.64 6.88 5.09 3.55 4.41 4.32 3.36 1.70 0.00 7.30

5.58 4.95 6.25 3.17 4.62 3.71

a. Kc1

b. Kc2

Ø Kebutuhan air bersih di sawah (NFR) maksimum terdapat pada bulan Desember periode 15 harian I, yaitu sebesar 11.29 mm/hari atau 1.31 lt/dt/ha

Tabel Kebutuhan Air Selama Penyiapan Lahan

Eo + P T = 30 hari T = 45 hari

mm/hari S = 250 mm S = 300 mm S = 250 mm S = 300 mm

5.0 11.1 12.7 8.4 9.5

5.5 11.4 13.0 8.8 9.8

6.0 1.7 13.3 9.1 10.1

6.5 12.0 13.6 9.4 10.4

7.0 12.3 13.9 9.8 10.8

7.5 12.6 14.2 10.1 11.1

8.0 13.0 14.5 10.5 11.4

8.5 13.3 14.8 10.8 11.8

9.0 13.6 15.2 11.2 12.1

9.5 14.0 15.5 11.6 12.5

10.0 14.3 15.8 12.0 12.9

10.5 14.7 16.2 12.4 13.2

11.0 15.0 16.5 12.8 13.6

NO SALURANPETAK YANG DIAIRI

LUAS (ha)

1 A1KA 150.992 1.35 254.80 0.252 A2KI 99.91 1.35 168.60 0.173 A2KA 194.75 1.35 328.64 0.334 A3KI 181.35 1.35 306.03 0.315 A3KA 152.82 1.35 257.88 0.266 A4KI 117.64 1.35 198.52 0.207 A4KA 97.94 1.35 165.27 0.178 A5KI 126.60 1.35 213.64 0.219 A5KA 80.58 1.35 135.98 0.14

10 A6KI 156.60 1.35 264.25 0.2611 A6KA 157.16 1.35 265.20 0.2712 A7KI 142.23 1.35 240.01 0.2413 A7KA 157.48 1.35 265.75 0.2714 B1KI 180.20 1.35 304.09 0.3015 B1KA 124.71 1.35 210.45 0.2116 B2KI 147.38 1.35 248.70 0.2517 B2KA 162.67 1.35 274.51 0.2718 B3KI 150.31 1.35 253.65 0.2519 B3KA 183.65 1.35 309.91 0.3120 B4KI 203.71 1.35 343.76 0.3421 B4KA 248.54 1.35 419.41 0.4222 B5KI 256.77 1.35 433.30 0.4325 B5KA 195.46 1.35 329.84 0.33

NFR Maks (l/dt/ha)

KAPASITAS Q (l/dt)

KAPASITAS Q (m3/dt)

NO. PETAK

Tabel 4.12 Dimensi Saluran

NO. SALURANQ

mV A

b/h h (m) b (m)m/dt

1 SP 1 3.47 1.50 0.60 5.789 3.0 1.134 3.4032 SP 2 5.16 1.50 0.65 7.940 3.5 1.260 4.4113 SS1 2.31 1.50 0.55 4.205 2.5 1.025 2.5634 SS2 1.75 1.50 0.55 3.179 2.5 0.892 2.2295 SS3 1.38 1.00 0.53 2.613 2.0 0.933 1.8676 SS4 1.04 1.00 0.52 1.991 2.0 0.815 1.6297 SS5 0.51 1.00 0.45 1.124 2.0 0.612 1.2248 SS6 3.22 1.50 0.60 5.360 3.0 1.091 3.2749 SS7 2.09 1.50 0.60 3.483 2.5 0.933 2.333

10 SS8 1.53 1.50 0.55 2.775 2.5 0.833 2.08211 SS9 0.76 1.00 0.50 1.526 2.0 0.713 1.42712 SS10 0.85 1.00 0.50 1.701 2 0.753 1.50613 SS11 0.59 1.00 0.45 1.309 2 0.661 1.32114 SS12 0.26 1.00 0.30 0.860 1 0.656 0.656

L ∆hSP 1 5.6 280000 31.99 32SP 2 1.02 51000 5.69 6SS1 2.63 131500 15.22 15SS2 2.6 130000 18.12 18SS3 1.8 90000 11.76 12SS4 1.62 81000 12.22 12SS5 2.37 118500 19.60 20SS6 3.43 171500 20.62 21SS7 2.86 143000 22.32 22SS8 2.6 130000 19.84 20SS9 2.8 140000 23.31 23

SS10 3.03 151500 23.46 24SS11 2.54 127000 18.97 19SS12 2.8 140000 11.83 12

m3/dt m2

Tabel 4.12 Dimensi Saluran

P R I Tinggi Jagaan(m) (m) F (m)

7.492 0.773 1.142 0.68.954 0.887 1.116 0.66.260 0.672 1.157 0.65.443 0.584 1.394 0.64.506 0.580 1.307 0.53.933 0.506 1.508 0.52.955 0.380 1.654 0.57.209 0.744 1.203 0.65.697 0.611 1.561 0.65.086 0.546 1.526 0.63.444 0.443 1.665 0.53.636 0.468 1.549 0.53.190 0.410 1.494 0.52.511 0.343 0.845 0.3

x 10-4

NO. SALURANQ

m cV A

b/h h (m) b (m) P(m) R(m)M3/dt m/dt m2

1 SP 1 2.18 1.502 SS1 1.28 1.003 SS2 0.71 1.004 SS3 0.35 1.005 SP 2 4.53 1.506 SS4 2.09 1.507 SS5 1.53 1.508 SS6 0.76 1.009 SS7 0.85 1.00

10 SS8 0.59 1.0011 SS9 0.26 1.00

I

x 10-4

tabel perhitungan evapotranspirasi potensial dengan metode penmann

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