Analisis Vegetasi Pohon di Sekitar Mata-air Kawasan Taman Mumbul, Sangeh, Abiansemal, Badung, Bali

KOMANG DEAN ANANDA, Dr. Retno Peni Sancayaningsih, M.Sc.

2014 | Skripsi | BIOLOGI

Indonesia merupakan negara yang memiliki air melimpah, namun daya tampungnya masih sangat rendah, terlihat apabila musim hujan terjadi banjir dan pada saat musim kemarau terjadi kekeringan. Untuk menjaga ketersediaan air, maka diperlukan adanya konservasi mata-air sebagai pemenuh kebutuhan akan air. Mata-air didapat dari keluaran air tanah, sehingga keberadaan air tanah harus selalu terjaga. Adanya tegakan vegetasi pohon di suatu lahan memberikan peran penting menjaga stabilitas air tanah. Oleh karena itu, penelitian ini bertujuan untuk mempelajari struktur vegetasi pohon di Daerah Tangkapan Air (DTA) serta laju infiltrasi air hujan pada DTA tersebut sebagai salah satu upaya konservasi mata-air. Penelitian dilakukan di DTA kawasan Taman Mumbul, Desa Sangeh, Kecamatan Abiansemal, Kabupaten Badung, Provinsi Bali pada bulan Maret � Juli 2014. Analisis vegetasi pohon dilakukan dengan Point of Center Quarter Method (PCQM) dan pengukuran laju infiltrasi dengan menggunakan Aplikasi Model Hujan-Aliran. Dari hasil penelitian, diperoleh jumlah individu spesies terbanyak di area sebelah timur Pura Utama Taman Mumbul yakni Tectona grandis/Jati dan sebelah barat Pura Utama Taman Mumbul yakni, Theobroma cacao/Cokelat. Nilai INP tertinggi dimiliki oleh Tectona grandis/Jati sebesar 370,43% (timur) dan Cocos nucifera/Kelapa sebesar 150,46% (barat). Indeks Keanekaragaman (H�) di kedua area (timur dan barat) tergolong rendah. Indeks Kemerataan (e) di area timur tergolong rendah dan di area sebelah barat tergolong sedang. Laju infiltrasi terbesar dengan persentase retensi tertinggi mencapai 86% (rumput dan semak) yakni, plot pada elevasi lahan datar, diikuti landai, dan miring berturut-turut 82% (rumput) dan 79% (semak) serta 45% (rumput) dan 59% (semak). Waktu tunggu air hujan terlimpas pada kategori elevasi lahan miring adalah yang paling singkat, yakni dengan rata-rata 10,5s, diikuti elevasi lahan landai dan datar. Jumlah debit mata-air di 8 titik sumber mengalami penurunan pada saat musim kemarau. Penurunan jumlah debit mata-air yang terendah yakni 19,33% pada mata-air di titik sumber ke-IV dan yang tertinggi mencapai 44,80% yakni pada mata-air di titik sumber ke-VI. Keadaan tersebut menggambarkan pentingnya komposisi vegetasi yang baik agar dapat membantu menjaga ketersediaan air di dalam tanah pada musim kemarau yang suplai air tanahnya rendah akibat rendahnya curah hujan.

Indonesia is a country that has abundant water, but its capacity is still very low, visible when the rainy season comes floods and during dry season occurs drought. To maintain the availability of water, it is necessary to have the springs conservation as fulfilling the need for water. Springs derived from ground water output, so the presence of groundwater should always be maintained. The presence of vegetation stands of trees in the area gives an important role to maintain the stability of the groundwater. Therefore, this research aims to study the structure of the tree vegetation in the Catchment Area as well as the infiltration rate of rain water on the Catchment Area as one of the Springs conservation efforts. The study was conducted at Catchment Area in Taman Mumbul, Sangeh Village, Abiansemal District, Badung Regency, Province of Bali on March-July 2014. Tree vegetation analysis performed by Point of Center Quarter Method (PCQM) and infiltration rate measurements using Rainwater Runoff Model. From the research, obtained the highest number of individual species in the east area of Pura Utama Taman Mumbul is Tectona grandis/Teak and west area of Pura Utama Taman Mumbul is Theobroma cacao/Cacao. The highest INP owned by Tectona grandis/Teak by 370.43% (east) and Cocos nucifera/Coconut by 150.46% (west). Diversity Index (H') in both areas (east and west) is low. Evenness Index (e) in the eastern area was low and in the west area classified as medium. The biggest infiltration rate with the highest retention percentage was 86% (grass and shrub) based on flat land elevation category, followed by ramps and slopping, respectively 82% (grass); 79% (shrub) and 45% (grass); 59% (shrub). Time for the first time rainwater runoff on sloping land elevation category is the shortest, i.e., an average 10,5s. The number of springs discharge in 8 point sources has decreased during the dry season. The lowest decrease of springs is about 19.33% on the springs IV and the highest reaches 44.80% on the springs VI. That situation illustrates the importance of a good composition of vegetation in order to help keep the water availability in the soil during the dry season groundwater supply low due to low rainfall.

Kata Kunci : Analisis Vegetasi, Mata-air, Infiltrasi, Air Tanah, Konservasi Air/ Vegetation Analysis, Springs, Infiltration, Groundwater, Water Conservation