Analysis of Raw Water Availability for Downstream Needs

in Geunang Uyat Small Dam Panton Reu

Sub-district West Aceh District

Muhammad Ikhsan

, Lissa Opirina

and Zairi Ulul Azmi

Civil Engineering Department, Teuku Umar University, Alue Peunyareng, Meulaboh, Indonesia

Department of Civil Engineering, Teuku Umar University, Meulaboh, Indonesia

Keywords: Irrigation, Small Dam, Downstream Needs, Geunang Uyat.

Abstract: Panton Reu Sub-district is one of area in Aceh province located in West Aceh district, which has potential

of lack of raw water if the dry season or drought comes . The number of residents of Panton Reu sub-district

in 2015 according to Central Bureau of Statistics (BPS) of West Aceh is 6,146 people with an area of 83.04

km2. the majority of local people are farmers. Total rice field in this area is ± 515 hectares with a level of

water needs large enough. Geunang Uyat small dam can be utilized for clean water and irrigation needs in

Panton Reu. The purpose of this research to analyze the amount of downstream requirement ie for irrigation

and domestic and non domestic needs. The result of this research is the total discharge of Geunang Uyat small

dam is 0,174 m

, The maximum requirement for plants is 1.33l /s/ ha and the irrigation water requirement is

2.04 l/s/ha. Domestic and non-domestic water requirements planned for this Geunang Uyat embung can not

be met due to very limited discharge. So the existing discharge capacity in Geunang Uyat small dam only able

to fulfill the needs of rice fields water.

1 BACKGROUND

Water as a basic necessity for living will always

increase as the population grows. Increasing water

demand is often not accompanied by adequate water

supply. Limitations of raw water, both surface, rain

and ground water caused by lack of development in

water resources sector for example in water resources

Indonesia located in the tropics is a country that

has a sufficient level of water availability. However,

Indonesia has a real constraint in meeting the needs

of water due to distribution and coupled with uneven

distribution patterns of the population, so that the

available water does not always meet the needs of the

community, both in terms of quantity and quality. The

Earth has a huge potential that is about 1.454 million

km, with a composition of 97.5% of sea water and

2.5% of fresh water, water in the form of surface

water (rivers and lakes) and 0.4% of ground water

(wells and springs).

Panton Reu Sub-district is one of area in Aceh

province located in West Aceh district, which has

potential of lack of raw water if the dry season or

drought comes . The number of residents of Panton

Reu sub-district in 2015 according to Central Bureau

of Statistics (BPS) of West Aceh is 6,146 people with

an area of 83.04 km2. the majority of local people are

farmers. Total rice field in this area is ± 515 hectares

with a level of water needs large enough. Geunang

Uyat small dam can be utilized for clean water and

irrigation needs in this area.

2 LITERATURE REVIEW

2.1 Irrigation Water Requirement

The irrigation water requirement is the amount of

water volume required to meet evaporation needs,

water loss, water requirements for plants with respect

to the amount of water provided by nature through

rainfall and ground water contributions. Rice water

requirement for rice is determined by the following

factors: land preparation, consumptive use,

percolation and seepage, effective change of water

layer and rainfall.

Ikhsan, M., Opirina, L. and Azmi, Z.

Analysis of Raw Water Availability for Downstream Needs in Geunang Uyat Small Dam Panton Reu Sub-district West Aceh District.

DOI: 10.5220/0010041202450250

In Proceedings of the 3rd International Conference of Computer, Environment, Agriculture, Social Science, Health Science, Engineering and Technology (ICEST 2018), pages 245-250

ISBN: 978-989-758-496-1

245

2.2 Hydrological Analysis

The calculation of the rainfall plan used to predict the

amount of rain with a certain repeat period. Based on

the rainfall the plan is then searched for the intensity

of rain used to look for flood discharge plans. To

predict the rainfall plan is done by frequency analysis

of rain data.

Log Type III method when described on

logarithmic probability paper will form a straight line

equation, so it can be expressed as mathematical

model with the following equation :

Y = Y + k .S (1)

2.2.1 Chi-Square Test Alignment

To determine the pattern of distribution of the most

appropriate average rainfall data from several

statistical distribution methods that have been done,

the alignment test is conducted. The chi-square

alignment test uses the formula:

(2)

2.2.2 Potential Evapotranspiration

Evapotranspiration is evaporation of the land surface

overgrown with plants. related to the plant, evapo-

transpiration is consumptive water requirement

defined as the total evaporation of the land and water

required by the plant..

 



eeufWRnWcET 



 ..1.

(3)



1 RnRsRn 



(4)

)/5,025,0( NnRaRs 

(5)

)/(.)(.)(

NnfefTfRn



(6)















100

127,0)(

(2.13)

100



(7)

2.2.3 Effective Rainfall

Effective rainfall is the rainfall that plummets in area

and used for crops to growth. Determination of

effective rainfall is based on every half monthly, that

is 70% rain from rainy chance fulfilled 80% or chance

to fail 20% :

%70

)(

%80

bulansetengahR

(8)

%100



n

(9)

2.2.4 Affiliations

The equations used to determine the net field

requirment (NFR) and irrigation water needs (DR) are

as follows (Yulianur, 2005):

WLRRPETNFR









(10)

(11)

2.3 Projection of Population Growth

Predicted population can be obtained by population

projection. Population projection based on population

census. Here the population projection is not only a

few years after the census but may be several decades

after the census. Taking into account the rate of

development of the population of the past, the

statistical method is the closest approach to

estimating the number of people in the future.

There are several methods that can be used to

analyze future population growth.

2.3.1 Arithmetic Method

This method is usually referred to as an average loss.

This method used when the data periodically shows

the same number of additions each year. This occurs

in cities with small area, low economic growth rate

and city development is not too fast.

= P

+{ P

.Ka(r.n)} (12)

2.3.2 Geometric Method

For the purposes of population projection, this

method is used when data shows a rapid increase over

time. Thus population growth where growth rates are

the same or constant for each year.

Pn = Po ( 1 + r )

(13)

𝑋





𝑂𝑖  𝐸𝑖

𝐸𝑖

𝑛

𝑖0

DR =

64,8e

NFR

ICEST 2018 - 3rd International Conference of Computer, Environment, Agriculture, Social Science, Health Science, Engineering and

Technology

246

2.4 Raw Water

Raw water is water used as a source for water

treatment. Raw water can come from a variety of

water resources. Understanding clean water is water

that is free from substances dissolved and have

qualified quality so that can be consumed as drinking

water. But not always clean water can be interpreted

as water that can be directly consumed or drunk,

because the water used to support activities such as

bathing, washing, irrigation, livestock, industry, and

fisheries need clean water whose water quality is not

necessary such as drinking water. Sources of raw

water that can be used for the provision of clean water

that is rain water, surface water, and ground water.

The need for clean water is an unlimited and

sustainable need. While the need for water supply and

service from time to time is increasing, which is

sometimes not matched by service capability. This

increase in demand is due to the increase of

population, the increasing of citizen life status and the

development of city/service area or things related to

the improvement of socio-economic condition of the

people.

2.4.1 Domestic Water Requirement

The clean water needed for daily activities is referred

to as domestic demand in this case including water for

drinking, cooking, cleaning the toilets and so on.

The basic needs of the domestic is the need for

clean water for the residents of the housing

environment are limited to household necessities such

as bathing, drinking, cooking, and others (Ministry of

Public Works, "Maximum Water Requirements

Day").

To estimate the current and future amount of

domestic water demand is calculated based on

population, population growth rate and per capita

water requirement. The per capita water requirement

is influenced by physical activity and habit or welfare

level. Therefore, in estimating the amount of

domestic water needs to distinguish between the

needs of water for urban residents (urban areas) and

rural areas (rural). The differentiation of water

demand is done with the consideration that people in

urban areas tend to use more water than the

population in the rural area. The amount of water

consumption can refer to the various standards that

have been published.

2.4.2 Non Domestic Water Requirement

The non-domestic basic water requirement is a water

requirement for residents outside the housing

environment (Ministry of Public Works, "Maximum

Water Requirements Day"). The need for non

domestic water is often also called urban water needs

(municipal). The need for clean water is determined

by the number of non-domestic consumers that

include office facilities (government and private),

places of worship (mosque, church, etc.), education

(schools), commercial (shop, hotel), public (market,

terminals) and Industry (Ikhsan, 2013).

Non-domestic sector analysis is conducted by

holding on to the latest growth data analysis of

existing socio-economic facilities in the planning

area. Non-domestic water requirements for cities can

be divided into several categories:

1. City Category I (Metro)

2. Category City II (Big City)

3. City Category III (Medium City)

4. City Category IV (Small Town)

5. Cities Category V (Village)

The amount of urban water demand can be

obtained by a percentage of the total household needs,

ranging from 25-40% of household water needs. The

40% rate applies specifically to metropolitan cities

with very high population density such as Jakarta.

Meanwhile, to obtain the amount of water demand

in a region, the equation is used to multiply the

number of users with the standard water requirement

for each type of use (Ikhsan, 2013).

Qy = dy x Py (13)

2.5 Study Area

This study was conducted at the location of

development of small dam Geunang Uyat District

Panton Reu Sub district West Aceh district, as shown

in Figure 1.

Figure 1: Study area

Analysis of Raw Water Availability for Downstream Needs in Geunang Uyat Small Dam Panton Reu Sub-district West Aceh District

247

3 RESULT AND DISCUSION

3.1 Maximum Monthly Rainfall

The rainfall data used is the maximum monthly

rainfall data each year from the rain gauge station.

The maximum monthly rainfall for 10 years is from

2005-2014.

Table 1: Maximum monthly rainfall

No Year

Max

1

2005

343

2

2006

538

3

2007

318.3

4

2008

398

5

2009

276

6

2010

260

7

2011

336.4

8

2012

309

9

2013

468

10

2014

265

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The signed Consent ensures that the publisher has the

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The copyright form is located on the authors’

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Figure 1: Maximum monthly rainfall

3.2 Potential Evapotranspiration

This calculation is done by using climatology data,

result of calculation can be seen in table 2

Table 2. Potential Evapotranspiration

No Mounth mm/day mm/month

1 Janua

y 3.937 115.338

2Februa

y 4.119 115.338

3Ma

ch 4.804 148.927

4 April 4.111 123.321

5 Mei 3.667 113.671

6 June 3.638 109.136

7 July 3.718 115.265

8 Augus

4.158 128.892

9Septembe

4.289 128.660

10 Octobe

4.450 137.962

11 Novembe

3.716 111.470

12 Decembe

3.466 107.453

We can see the magnitude of potential

evapotranspiration (ETo) that occurred in the District

of Panton Reu, West Aceh regency. Maximum

evapotranspiration value (ETo) occurs in March,

reaching 4,804 mm/day or 148,927 mm/ month.

Evapotranspiration occurs when there is enough

water (from participation or irrigation) to meet

optimum growth. The greater the area of watered

agriculture the greater the need for water for

evapotranspiration.

3.3 Effective Rainfall

Determination of effective rainfall is based on every

half monthly, that is 70% rain from rainy chance

fulfilled 80% or 20% chance of failure. For that can

be seen in table 3

Table 3. Effective rainfall

3.4 Rice and Irrigation Water

Requirement

Irrigation water demand is the amount of water

volume required to meet evaporation needs, water

ICEST 2018 - 3rd International Conference of Computer, Environment, Agriculture, Social Science, Health Science, Engineering and

Technology

248

loss, water requirements for crops with respect to the

amount of water provided by nature through rainfall

and groundwater contribution. In this study the water

source used to meet the needs of water irrigation

water that is in embung Geunang To meet the needs

of irrigation water in the District of Panton Reu West

Aceh district. The calculation of irrigation water

demand can be seen in Table 4.

Table 4. Rice and irrigation water requirement

Irrigation water demand is the amount of water

volume required to meet evaporation needs, water

loss, water requirements for crops with respect to the

amount of water provided by nature through rainfall

and groundwater contribution.

3.5 Population Projection

Population projection based on population census,

here population projection not only a few years after

census but maybe until several decades after census.

With regard to the rate of population growth in the

past, the statistical method is the closest method to

estimate the population in the future. In research

conducted in this Panton Reu dikecamatan this

population projection will calculated using arithmetic

method with 10 year scale. The available data is the

number of population in 2015 which amounted to

6146 people, This data is taken from the West Aceh

District Statistics Agency. Next will look for the

number of residents in the future from 2016 - 2024.

Table 5: projected number of people of 10 years

Figure 2. graph of population increase each year

explains the graph of population increase each

year in the District of Panton Reu, West Aceh regency

for a 10-year period from 2015 to 2024. Panton Reu

district has a population density of 1.85% every year.

This number continues to increase in the next few

years as time goes by.

3.6 Domestic Water Demand

The basic needs of the domestic is the need for clean

water for residents of the housing environment is

limited to household needs such as bathing, drinking,

cooking, and others. To estimate the current and

future amount of domestic water demand is calculated

based on population, population growth rate and per

capita water requirement. The per capita water

requirement is influenced by physical activity and

habit or welfare level. Therefore, in estimating the

amount of domestic water needs to distinguish

between the needs of water for urban residents (urban

areas) and rural areas (rural). The existence of

different water needs was done with the consideration

that people in urban areas tend to use more water than

the population in the rural area.

Analysis of Raw Water Availability for Downstream Needs in Geunang Uyat Small Dam Panton Reu Sub-district West Aceh District

249

Table 4. Domestic Water Requirement of 10 year

large discharge needed to meet domestic water needs

every year. While the remaining debit that existed in

Geunang Uyat Embung after meeting the needs of

rice and irrigation water is only 0.159 m3. While the

debit that must be met to meet the needs of domestic

water for one year alone for example in 2015

amounted to 429 m3. The huge amount of domestic

water demand in each year, it can be concluded that

the Geunang Uyat embungs are unable to meet

domestic and non-domestic water needs due to the

insufficient capacity of the planned capacity.

4 CONCLUSION

1. From the analysis of the frequency of rain data with

some distribution of gumbel, normal, normal log

and log person III then obtained the suitable

distribution used was the distribution of log person

III with Cs ≠ 0 and the calculation Cs = 0.7884 for

this distribution log person III is eligible.

2. The planned cropping pattern in Panton Reu area is

Palawija - Padi - Rice with planting planning July

1st. This planning is based on the needs of wetland

water and the requirement for maximum irrigation

water occurs in July with NFR = 1.33 l/ s/h and DR

= 2.04 l /s/ h.

3. The number of residents in Kecamatan Panton Reu

if it is predicted in the 10 year period from 2015-

2024 amounted to 93392,43 people with a growth

rate of 1.85% / year.

4. Domestic water needs are planned by utilizing

Geunang Uyat embungs can not be realized

because the debit that must be met to meet the

domestic water needs for one year only in 2015

amounted to 429 m3 while the residual debit

existing in Geunang Uyat embung only 0.166 m3.

So the existing water capacity in Geunang Uyat

small dam only can fulfill the needs of field rice

water.

ACKNOWLEDGEMENTS

On this occasion the author would like to say thank

God to Allah SWT who has given health so that can

finish this research. thanks to all those who have

assisted in this research, Dean of Faculty of

Engineering Teuku Umar University Dr. Ir. H.

Komala Pontas, chairman of the Department of Civil

Engineering Mrs. Lissa Opirina, S.T., M.T. to the

students who have helped the author also thank you

very much. Hopefully this research is useful. Amen.

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Technology

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