VEGETATED POND MODELS TO IMPROVE INFILTRATION RATE WITH RAINFALL INTENSITY VARIATIONS

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1 International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 10, October 2017, pp , Article ID: IJCIET_08_10_070 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed VEGETATED POND MODELS TO IMPROVE INFILTRATION RATE WITH RAINFALL INTENSITY VARIATIONS Abd. Rakhin Civil Engineering Department, Muhammadiyah University of Makassar, Indonesia Nurnawaty Civil Engineering Department, The Muhammadiyah University of Makassar, Indonesia ABSTRACT Changes in the function of the catchment area as a means that can accommodate excess water during the rainfall requires a way to increase infiltration capacity, among others by modeling the vegetation recharge pond with the variation of rainfall intensity and how the tree root effectiveness in improving the function of absorption. This research was conducted experimentally in laboratory with physical model to observe pond with root vegetation on infiltration rate on soil surface due to variation of rainfall intensity (I) and duration of time (t). The results showed rainfall Intensity 5 year (I 5 ) = mm/h, I 10 = mm/h, and I 25 = 344,900 mm/hr with four different root cover variations 1 st Model 2 nd Model and 3 rd Model increment of infiltration rate is significant where pond without vegetation cover has lower infiltration capacity than the variation of 1, 2 and 3 models which increases.. For the highest level of soil infiltration is in the intensity of rainfall I 5 without using tree media and decreased at the intensity of I 10 and I 25. Key words: infiltration capacity, rainfall intensity, recharge pond, the root tree. Cite this Article: Abd. Rakhin and Nurnawaty, Vegetated Pond Models to Improve Infiltration Rate with Rainfall Intensity Variations. International Journal of Civil Engineering and Technology, 8(10), 2017, pp INTRODUCTION Urban development is characterized by increasing population resulting in reclaimed the land into residential areas so that there is a change in the function of the area of the recharge area as a means that can accommodate excess water during the rain. With such a situation when the rainy season arrives, there are some areas that are flooded. The problem is how to improve water absorption to avoid runoff in the rainy season and speed up the process of infiltration of water into the soil or how to increase the infiltration capacity by modeling the vegetation absorption pond with the variation of rainfall intensity of the region and how the tree root as vegetation effectiveness in improving the function of absorption editor@iaeme.com

2 Vegetated Pond Models to Improve Infiltration Rate with Rainfall Intensity Variations 2. MATERIALS & EXPERIMENTAL PROCEDURES The study was conducted experimentally in the laboratory with the following research design 2.1. Physical Model Tools The main equipment used in the research of the potential increase of infiltration in the vegetated pond model with variation of rainfall intensity is Rainfall Simulator in Figure 1 Figure 1 View of rainfall simulator The rainfall simulator tool consists of : main experimental bath,6 pieces left and 6 pieces right side drainage measuring vessel, water reservoir and waste output water filter vessel, control panel, Reservoir (rainfall source), water container from all drains, valve control panels drainage vessels from drain, manometers (23 points for two different axes), vessels as water sources to simulate river flow and the rain nozzle on the gantry (sit hanging) Stages Running Test Running test-1. Measurement of infiltration on soil without vegetation cover. Running test-2. Measurement of infiltration with the addition of tree vegetation model. (the stage is done with 3 variations, which is running with Model 1, Model 2 and model 3) 2.3. Data and Research Variables In accordance with the purpose of this study, the test is performed by physical laboratory model with literature study related to infiltration. This physical model is intended to observe the effect of tree vegetation on the infiltration rate on the soil surface due to variations in rainfall intensity (I), time duration (t). and infiltration volume (V) 2.4. Vegetated Ponds Model The physical model of the pond is vegetated by adjusting the shelter on a rainfall device carried out as shown in Figure editor@iaeme.com

3 Abd. Rakhin and Nurnawaty (a) Pond model without vegetation (b) Pond Model-1 with 1 tree (c ) Pond Model-2 with 3 tree (c) Pond Model-3 with 6 tree Figure 2 Gambar 2 Pond Models with and without vegetation 3. THEORITICAL REVIEW 3.1. Rainfall Intensity Rainfall intensity is a function of the amount of rainfall that occurs and inversely proportional to the time of the incident. This means that the amount of rainfall that occurs will be higher intensity if it occurs in a shorter period of time, and vice versa or can be presented in the form of equation as follows (Sosrodarsono and Takeda, 1977): I = R.t (- 1) (1) where: I = rainfall intensity (mm / h) R = precipitation / amount of rainfall (mm) t = time period (minutes) The rainfall intensity value is different caused the duration or frequency of rainfall The formulas of rainfall intensity associated with compiled as experimental formulas. One of them is used in Japan better known as Mononobe formula and is the formula of rainfall intensity for short-term rainfall (Sosrodarsono and Takeda, 1977) are as follows: ( ) (2) Where: I = rainfall intensity (mm / h) t = duration of rainfall (hours) = maximum rainfall within 24 hours (mm) R editor@iaeme.com

4 Vegetated Pond Models to Improve Infiltration Rate with Rainfall Intensity Variations Distribution of Rainfall Region (Regional Distribution) The precipitation required for the preparation of a water utilization design and flood control design is the average rainfall in the entire area concerned, not the rainfall at a given point. This rainfall is called rainfall region / regional is expressed in mm. Qualitatively rainfall intensity is also called the degree of rainfall, as shown in table 1. Table 1 Rainfall and rainfall intensity Rainfall level Rainfall intensity (mm/h) condition very weak rainfall < 1,20 The soil is slightly wet or dampened slightly. weak rainfall 1,2 3,00 The soil gets wet all over, but it's hard to make a puddle. normal rainfall 3,00 18,0 Can be made puddle and the sound of rainfall sounds. heavy rain 18,0 60,0 Water is inundated all over the ground and the rain sounds from the puddles. Very heavy rain >60,0 Rain was shed, drains and drainage overflowed. Sumber : Suripin, (2004) Use of Rainfall Simulator The formula used to calculate the artificial rainfall intensity by simulating the calculation of the rainfall intensity of the plan follows the equation introduced by Kusumastuti et al (1994) in Arfan (2012) as follows: ( ) Where : I = rainfall intensity (mm / h) V = volume of water in container (ml) A = area of container (cm2) t = time (minutes) (3) If the rain intensity (I) is greater than the infiltration capacity (f) there will be a puddle above the soil surface. At one time the puddles will overflow and the overflow of water is accommodated in a container. By knowing the rain intensity (I), the volume of the container in the container and the height of the puddle, it can be calculated infiltration capacity (f) (Triatmodjo, 2008) 3.2. Infiltration Infiltration can be defined as the vertical flow of water into the soil through the surface of the soil (Triatmojo, 2008 and Harianto, 2011), while Sosrodarsono (1987), defines infiltration as the process of entering rainfall into the soil and descending to the groundwater surface. Events occurring against falling rainfall after reaching the ground are the movement of water as surface runoff and infiltration. The proportion of both events depends on the magnitude of the intensity of the rainfall on the infiltration capacity Plant Roots The absorption of water in the soil is carried out by the root organ, the water absorbed by the roots is channeled through the xylem vessels to the leaf organ. In leaves only a small portion editor@iaeme.com

5 Intensitas Curah Hujan ( mm/jam ) Abd. Rakhin and Nurnawaty of the water is used for metabolic processes while most of the other is expelled to the atmosphere by the leaves through a transpiration process. Water required by plants for photosynthesis is obtained from the soil. Water is an essential component of living systems. In plant cells that are growing 80-90% of it is water. Plants continued absorb and excrete water (transpiration). Therefore, water balance in plants includes three main parts, namely: groundwater, water absorption by roots, water transport and nutrients through xylem and the expenditure of water vapor into the atmosphere through transpiration the plants used are pucuk merah (Oleina Syzygium) 3.4. Vegetated Pond The physical model of the vegetated pond of research is designed by researchers based on literature studies of research results using a tub on a rainfall simulator tool with variations of the root of the vegetation used for the study. The size of the physical model is: Size of sample media (p x l x t): (100 x 120 x 50) cm 3 4. RESULT 4.1. Analysis of Rainfall Intensity Rainfall intensity analysis using Mononobe s formula because rainfall data obtained is daily rainfall data with rainfall Intensity of 5, 10 and 25 year return period measurements take 5 to 60 minutes, obtained from consecutive calculations: 246,841 mm, 290,335 mm and 344,900 mm. Recapitulation value in Table 2 and Figure 3 Table 2 Result of Calculation Rainfall Intensity Calculation No Waktu I 5 I 10 I 25 (menit) mm/jam mm/jam mm/jam Source : The calculation results t ( menit ) I5 I10 I25 Figure 3 Relationship between rainfall intensity and time editor@iaeme.com

6 Vegetated Pond Models to Improve Infiltration Rate with Rainfall Intensity Variations 4.2. Infiltration Rate with Tree covers Model The calculation results of the infiltration rate for each Models of rainfall intensity with different density of each rainfall intensity. Can be seen in the example calculation below: at rainfall intensity I 5 (246,335 mm / hour, calculation of infiltration rate Rainfall volume = I x t x A Where : rainfall intensity (I) = 246,335 mm/hr time (t) = 5 minute surface area (A) = mm 3 = cm 2 rainfall volume every 5 minute : V = = ml Infiltration vol = rainfall intensity vol runoff vol drain reservoir vol = = ml Infiltration rate = infiltration vol x (t/60) = x (5/60) = 20570,1 ml/hour = = 1,7142 cm/hr = 17,14 mm/hr For calculations in minutes, intensity, and subsequent models of the results in Table 3 Table 3 Infiltration Rate at Intensity I5 for three vegetations model Source : calculations result 4.3. Infiltration Capasity Observation of infiltration volume on soil samples with different densities for each intensity using three variations of intensity: I 5 = mm/h, I 10 = mm/h, and I 25 = 344,900 mm/hr with three different cover models: without cover versus, one tree cover (M1), three tree cover (M2), and six tree cover (M3). Graph of the relationship of infiltration and time volumes such as Fig. 4, Fig. 5 and Fig. 6 for the three variation of rainfall intensity editor@iaeme.com

7 Volume Infiltrasi (ml) Volume Infiltrasi (ml) VolumeInfiltrasi (ml) Abd. Rakhin and Nurnawaty Tanpa Tutupan I5 AK1 I5 AK3 I5 AK Waktu (Jam) Figure 4 Graph of infiltration volume I5, on observation without vegetation with three models Tanpa Tutupan I10 AK1 I10 AK3 I10 AK Waktu (Jam) Figure 5 Graph of infiltration volume I 10, on observation without vegetation with three models Tanpa Tutupan I25 AK1 I25 AK3 I25 AK Waktu (Jam) Figure 6 Graph of infiltration volume I 5, on observation without vegetation with three models 4.4. Increased Infiltration Rate Increasing infiltration rate in vegetated ponds for each intensity with three different variations of vegetation model are: one tree (Model 1), three trees (Model 2), and six trees (Model 3). The result of increasing infitration rate in the vegetated pond model showed in Table 4 and Fig 7. graph of the relationship of increasing infiltration rate and time editor@iaeme.com

8 Vegetated Pond Models to Improve Infiltration Rate with Rainfall Intensity Variations Souce : Calculations result Table 4 Indreasing Infiltration Rate Waktu t Laju Infitrasi I 5 Laju Infitrasi I 10 Laju Infitrasi I 25 (menit) Model 1 Model 2 Model 3ataModel 1 Model 2 Model 3ata Model 1 Model 2 Model 3ata Figure 7 Changes in Infiltration Rate, at Intensity I 5 (a), Intensity I 10 (b) and Intensity I 25 (c) for vegetated ponds with 3 variations Model editor@iaeme.com

9 Abd. Rakhin and Nurnawaty 5. CONCLUSIONS For all intensities, Infiltration rates of soil at I 5 ( mm/h), I 10 ( mm/h) and I 25 (344,900 mm/h) increased significantly where the infiltration capacity was lower in natural conditions without vegetation than the variations of model 1, model 2 and model 3 that increase according to the increasing number of trees. For the highest soil infiltration rate is found in rainfall intensity I 5 without vegetation and decreased at the intensity of I 10 and I 25. This happens because the level of soil density before the rain and after the rain which resulted in the compression by rain. ACKNOWLEDGEMENTS The authors thank to Ristekdikti who has funded this research, chairman and all staff LP3M Unismuh Makassar for permission and encouragement to conduct such studies for the benefit of science, thankful to Hidrology Laboratory Civil Engineering Muhammadiyah University Of Makassar, and all those who have helped the completion of this research REFERENCES [1] Arfan, H Pengujian Karakteristik Resapan dengan Variasi Intensitas Curah Hujan, Tingkat Kepadatan, dan Gradasi Tanah Daerah Pesisir. Prosiding PIT XXVII HATHI, Ambon [2] Arfan, H. Experimental Model of Infiltration Behaviour In Organic Soil. Proceedings of the International Symposium on Lowland Technology, Bali, Indonesia, (2012) [3] Asdak, Chay Hidrologi dan Pengelolaan Daerah Aliran Sungai, Gadjah Mada, University Press, Edisi keempat. [4] Bartens, J., Day, S. D., Harris, J. R., Wynn, T. M., and J. E. Dove Transpiration and root development of urban trees in structural soil storm water reservoirs. Environmental Management. 44: [5] Eliasson Sonja & Larsson Martin The Influence of Land-Use Change, Root Abundance and Macropores on Saturated Infiltration Rate (A Field Study on Western Java, Indonesia). Report of Minor Field Studies (MFS) Scholarship Programme, by the Swedish International Development Cooperation Agency (SIDA). [6] Gonzalez-Sosa, E., I. Braud, J. Dehotin, L. Lassabatère, R. Angulo-Jaramillo, M. Lagouy, F. Branger, C. Jacqueminet, S. Kermadi and K. Michel Impact of Land Use on the Hydraulic Properties of the Topsoil in a Small French Catchment. Hydrological Processes. 24(17): [7] Harto Sri Br, Analisis Hidrologi. PT Gramedia Pustaka Utama, Jakarta (1993). [8] Haryanto, Tri Investigasi Nilai Permeabilitas Tanah Berdasarkan Nilai Hasil CPTU. Prosiding Hasil Penelitian Takultas Teknik Uhhas, Vol. 6, Makassar [9] Hatt, Belinda E. Tim D. Fletcher, Ana Deletic Hydrologic and pollutant removal performance of storm water bio filtration systems at the field scale. Journal of Hydrology.365 (3 4): [10] Lange, B., P. Luscher, P.F. Germann Significance of Tree Root For Preferential Infiltration In Stagnic Soil. Hydrol. Earth Syst. Sci., 13, [11] Mao Lili, etc, Methods For Measuring Soil Infiltration: State of The Art. Int Agric and Biol Eng, 1 (1): [12] Munir, A. Syamsuddin, C. Suhardi, and M. Achmad. 2012, Simulation of Ground Water Contour at Coastal Area South Sulawesi. Proceedings of the International Symposium on Lowland Technology, Bali, Indonesia, editor@iaeme.com

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