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Rainwater Management for Agriculture and Life in the Household Scale

Susilawati 1* 1Engineering Faculty of Widya Mandira Catholic University, San Juan, str., Penfui-Kupang 85361

*sr.susi.dp@gmail.com

Keywords: Rainwater management, water for agriculture and life, household scale, Ferro-cement,mineralization. 

Abstract. East Nusatenggara Province has dried climate situation, which caused of the availability

of water for living very scarce. Some option have done do to this situation, for example by developing

many embung   (small reservoir) or water-trap series along the gully as gully plug. The problem

furthermore comes related with the operation and maintenance of these structure. That’s also

happened for between each household place are far each other. Rainwater management in the

household scale would be the way to cope the scarcity for this condition. The principle concept is

managing the rainfall water on the household field by catching runoff with several Ferro-cementstructure to keep rainwater not to flow away out from household field and use for agriculture or others.

Rainfall water on the roof are managed by rainwater catches canal structure that completed with

mineralization and filtration structure so could use as clean water for life. This structure has done as

a model at 4 household in Tli'u village. As a result, they have water for agriculture activity and life. 

Introduction

East Nusatenggara Province has dried climate situation, so the availability of water for living is

very scarce [1]. Some option have been done, for example by developing many embung (small

reservoir) [2]. An evaluation of embung systems development also have been done, particularly in

Sabu-Raijua Island, which includes: the infrastructure system review, operations and maintenance,institutional, community development, information systems and analysis of the benefits value. It can

 be concluded that the development of embung systems in Sabu-Raijua Island, have given some

 positive benefits. Several aspect need some attention, especially on the technically infrastructure

systems related to the proper target planning services, charging condition of the water in the embung  

and the speed of sedimentation rate. Less attention of the operation and maintenance system have

made the embung  does not work anymore after a short time. Similarly, the limited human resources

make the institutional system very poor. Keeping in a well planned community development, will be

supporting the technical aspects, but unfortunately also less attention as well. It can be said that the

development of embung  system on the island of Sabu-Raijua looks like a central government project,

 poor involvement of the local area officials, so is less support from local people.

Attention to technical infrastructure systems or rainwater harvesting system is urgently needed because the development of the existing embung  has less efficiency factor due to the evaporation and

sedimentation occurs. To overcome this case, it is necessary to consider the alternative waterresources development in this areas, which have a large evaporation and high sedimentation rate, such

as conservation reservoir that serves to capture rainwater, preserve it by letting the water soak into

the ground soils. Furthermore, it can be prepared dug wells to extract the water that has infiltrated to

ground water reservoir to give available water for agriculture and daily used. This alternative water

resource development is given the term as rain water management for agriculture (RWMA). This

system emphasizes the term of "management" which means that rain water managed optimally and

has not just rain water harvesting. Likewise, it is keep in mind as well that the system management

and maintenance has done participatory by people as well to meet the sustainability of the system.

Since 2010, Susilawati has tried to promote the water-trap series along the gully as gully plug to

get more water for agriculture and domestic-municipal-industry need. Based on the systems done by

 people in Daieko to get water by holding water flowing in the grooves of the natural drainage system

called as water trap, that was developed a simple system to manage water as form as rain water trap

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series such as simple embankments as gully plug [3]. This system was developed to cope floods and

droughts on small islands [4]. Furthermore, from the village of Daieko case studies, it has developed

for the entire island of Sabu [5]. From the observation of the reservoir system failure cause largely

sedimentation due to the cliffs erosion of reservoir design, the system was developed further by

adding a cliff reinforcement system with vetiver grass [6]. Due to various constraints in implementing

this system, especially concerning financial terms, further developed this system in household scale[7] which was implemented in four families in the Tli'u village. The most constraint of this system is

the operation and maintenance of these structures [8]. This obstacle strengthened again by dwelling

communities from each other. Fueled by this experience, so was developed of rain water management

for agriculture and the need to live in a household scale system. That’s also can be happened because

of between each household place are far each other (Fig. 1, 2 and 3). Rainwater management in the

household scale would be the way to cope the scarcity for this condition.

Figure 1 Tli’u village imagery in 2004 

Figure 2 Tli’u village imagery in 2010 

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Figure 3 Tli’u village imagery in 2015 

Rainwater Management Concept

The principle of rainwater management concept is managing the rainfall water on the household

yard by catching runoff with several Ferro-cement structure to keep rainwater not to flow out away

from household yard and use that for agriculture or others needs. Rainfall water on the roof are

managed by rainwater catches canal structure that completed with mineralization and filtration

structure so could use as clean water for life (Fig. 4).

Figure 4 Rainwater management concept

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Rainwater Management for Agriculture Application Model and Life in the Household Scale

This concept is being implemented in four households in the Tli'u Village. Several water wells that

trap rainwater are installed interconnected with each other, so as to get the water accommodated,

simply use the hand pump alone without the need for energy. The hydrological analysis have to be

done to get the yearly rain for availability water. Table 1 shows the plotting position analysis.

Followed by the plotting position graphic (Fig. 5) and dry-normal-wet yearly rainfall analysis (Table2).

Table 1 Plotting position analysis

Figure 5 Plotting position grafic

 No Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Des Total Rank Fa=100*m/(N+1)

1 1989 147 175 184 111 59 34 55 0 2 15 73 204 1059 2223 4.55

2 1990 380 229 205 67 62 2 0 0 0 0 0 454 1399 1951 9.09

3 1991 300 204 127 324 61 100 27 0 2 0 293 120 1558 1942 13.64

4 1992 302 130 235 99 50 51 0 0 0 0 126 373 1366 1886 18.18

5 1993 190 115 156 87 51 137 49 0 0 0 29 178 992 1827 22.73

6 1994 394 257 115 48 12 0 0 0 0 0 0 276 1102 1797 27.27

7 1995 137 228 147 163 0 15 0 0 94 104 322 293 1503 1691 31.82

8 1996 381 347 216 55 38 33 0 31 0 0 154 351 1606 1654 36.36

9 1997 381 632 86 13 21 0 34 0 0 0 49 438 1654 1606 40.91

10 1998 72 255 206 172 49 0 0 0 0 117 385 78 1334 1558 45.45

11 1999 545 199 342 380 7 23 0 0 0 41 236 169 1942 1518 50.00

12 2000 133 194 229 366 203 47 0 0 0 114 233 172 1691 1503 54.55

13 2002 315 205 114 122 0 0 0 0 0 0 98 229 1083 1399 59.09

14 2003 246 203 353 69 0 0 0 0 0 135 230 987 2223 1366 63.64

15 2004 247 487 462 27 129 23 0 0 0 0 62 390 1827 1334 68.18

16 2009 545 199 342 380 7 0 0 6 0 0 178 140 1797 1102 72.73

17 2010 478 522 27 55 146 44 9 10 33 20 205 337 1886 1083 77.27

18 2011 365 295 341 354 64 8 0 0 0 9 112 403 1951 1076 81.82

19 2012 54 291 0 90 0 0 0 0 3 5 5 413 861 1059 86.36

20 2013 285 463 0 0 0 48 55 0 0 23 0 202 1076 992 90.91

21 2014 172 226 248 167 56 142 89 20 0 0 57 341 1518 861 95.45

Piav = 289 278.9 196.9 150 48.33 33.67 15.14 3.19 6.381 27.76 135.6 311.8

0

500

1000

1500

2000

2500

1.0010.00100.00

P80: Pdry = 1200 mm

P20: Pwet = 1900 mm

P50: Pnor = 1600 mm

Pav = 1496.6 mm

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Table 2 Dry-normal-wet yearly rainfall analysis

Several steps have to be done during the implementation of this model, i.e.:

1.  When to do the survey in the study location, it must be observe how the runoff flowing, so thatcan be decided the location of the water well tank (Fig. 6)

2.  Then the catchment area of rainwater are determined for each water well, so it can be known thevolume of rainwater which can be captured and stored in the water wells

3.  The next step is determined the dimensions of the catchment water wells in accordance with the potential of rainwater that can be captured.

4.  The final step is the design drawings of the catchment water wells.The field area for each house-hold and the catchment area for water well are shown in Fig. 7-10.

Figure 6 Location of the water well and the runoff flowing to the well of Mr. Benyamin

Figure 7 Location of the water well and the runoff flowing to the well of Mr. Markus

Bulan Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Des Total (mm)

Piwet 367 354 250 190 61 43 19 4 8 35 172 396 1,900

Pinor 309 298 211 160 52 36 16 3 7 30 145 333 1,600

Pidry 232 224 158 120 39 27 12 3 5 22 109 250 1,200

ETo 129 121 139 149 169 162 185 204 205 213 180 141 1,997

 

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Figure 8 Location of the water well and the runoff flowing to the well of Mr. Hiller

Figure 9 Location of the water well and the runoff flowing to the well of Mr. Yusak

Figure 10 Field area and catchment area for 4 house-hold

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The construction of the water well contain of the Ferro-cement system as figured as Figure 11.

Figure 11 Ferro-cement water well system for rainwater captured and stored

The potential water which can be captured and stored are calculated as shown in Table 3.

Table 3 The potential rainwater which can be captured and stored to Ferro-cement  

Conclusion

The household water needs can be met by developing of rain water management system in the

household scale. Even still have excessive water, which can be used to meet the water needs of

agriculture and other businesses. It is suggested that the comparable between yard land area and

family members, must be considered in determining the capacity of rainwater well captured.  

References

[1] Susilawati CL and Adri G. Sooai, Management of rain-water system for agriculture during the

dry season to raise food security in small and rural islands of Indonesia. Research Report (competitive

grant), Kupang, 2012.

[2] Djoko Kirmanto, Regulation of the Minister of Public Works No. 06/PRT/M/ 2011 on Guidelines

for the Use of Water Resources (2011), 40-48.

[3] Susilawati CL, Rainwater Management for Agriculture in Daieko Village Hawu Mehara District,

Sabu-Raijua Regency, NTT Province. Journal SIPIL UNWIRA Vol 1 No.1 (2010), 51-58.

Family Areal (m2) 2,000 1,500 1,280 mm

Yusak 302 Pwet Pnor Pdry Coeff = 60%

CA FC-01 128 15,360 11,520 9,830

CA FC-02 174 20,880 15,660 13,363

Benyamin 1187 m3

m3

m3

CA FC-01 444 53,280 39,960 34,099

CA FC-02 282 33,840 25,380 21,658

CA FC-03 461 55,320 41,490 35,405

Markus 1340 m

3

m

3

m

3

drink 3.65 m

3

CA FC-01 404 48,480 36,360 31,027 personal 18 m3

CA FC-02 478 57,360 43,020 36,710

CA FC-03 458 54,960 41,220 35,174

Hiller 1434 m3

m3

m3

CA FC-01 368 44,160 33,120 28,262

CA FC-02 412 49,440 37,080 31,642

CA FC-03 654 78,480 58,860 50,227

Yusak's family

water needs can

still be met

2 l/person/day

15 l/person/day

for drink 

for personal

Requirement for 5

 person per family

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[4] Susilawati CL, Water Resource Conservation with the System of Water-trap Series to Cope Flood

and Drought on Small Island, Journal SIPIL UNWIRA Vol 2 No.1 (2011) 30 -38.

[5] Susilawati CL, Rainwater Management Model Development for Agriculture in the Savu Island

Semi-Arid Region, Civil Engineering Dimension Vol. 14 No. 1 (2012) 36-41.

[6] Susilawati CL, Water-trap Series Engineering with Vetiver Grass in Water Resources

Development which are Integrated and Sustainable, KoNTekS 7 Proceeding (2013) A55-A63.

[7] Susilawati CL, Sustainable Technology Innovation Inundated, Rain Water Management Scope of

Household, PIT-HATHI 31 Proceeding (2014) 51-62.

[8] Susilawati CL, Implementation Study of Technological Innovation in Addressing Problems of

Water Resources Management in NTT, PIT-HATHI 30 Proceeding (2013) 112-121.