SWRM : SUSTAINABLE WATER RESOURCES MANAGEMENT

1. MK. PENGELOLAAN SDALH SWRM:SUSTAINABLE WATER RESOURCES MANAGEMENT Smno.psdl.pdkl.ppsub2013

2. Ketikamusimhujantiba, tentunyainilahrahmat yang dianugerahkan Allah SWT kepadabumidanseisinya. Sebagaimanafirman-Nya : “ Dan Dialah yang meniupkananginsebagaipembawaberitagembirasebelumkedatanganrahmat-Nya (hujan); hinggaapabilaanginitutelahmembawaawanmendung, Kamihalaukesuatudaerah yang tandus, laluKamiturunkanhujandidaerahitu, makaKamikeluarkandengansebabhujanituberbagaimacambuah-buahan. SepertiitulahKamimembangkitkanorang-orang yang telahmati, mudah-mudahankamumengambilpelajaran” (Al-Qur’an Surah Al-A’raf [7]: 57)

3. Perhatikan pula Surah Al-An’am (6) ayat 6 : “ Apakahmerekatidakmemperhatikanberapabanyaknyagenerasi-generasi yang telahKamibinasakansebelummereka, padahal (generasiitu), telahKamiteguhkankedudukanmerekadimukabumi, yaituketeguhan yang belumpernahKamiberikankepadamu, danKamicurahkanhujan yang lebatatasmerekadanKamijadikansungai-sungaimengalirdibawahmereka, kemudianKamibinasakanmerekakarenadosamerekasendiri, dankamiciptakansesudahmerekagenerasi yang lain”

4. Water resources are sources of water that are useful or potentially useful to humans. Uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water. Fresh water is a renewable resource, yet the world's supply of clean, fresh water is steadily decreasing. Water demand already exceeds supply in many parts of the world and as the world population continues to rise, so too does the water demand. Awareness of the global importance of preserving water for ecosystem services has only recently emerged as, during the 20th century, more than half the world’s wetlands have been lost along with their valuable environmental services. Biodiversity-rich freshwater ecosystems are currently declining faster than marine or land ecosystems. The framework for allocating water resources to water users (where such a framework exists) is known as water rights.

5. Water management is the activity of planning, developing, distributing and optimum use of water resources under defined water polices and regulations. Hal iniberartibahwa: Management of water treatment of drinking water, industrial water, sewage or wastewater Management of water resources Management of flood protection Management of irrigation Management of the water table.

6. DAUR HIDROLOGI CURAH HUJAN intersepsi VEGETASI PERMUKAAN TANAH Aliran permukaan infiltrasi banjir CADANGAN SALURAN AIR TANAH Aliran bawah permukaan perkolasi Aliran air bawah tanah transpirasi AIR BAWAH TANAH evaporasi EVAPOTRANSPIRASI KEBOCORAN LIMPASAN

7. CURAH HUJAN: Air cairygturundariatmosferkepermukaandinyatakansbgkedalaman air pd permukaanmendatar (rainfall) Presipitasi: Banyaknyacurahan pd permukaanmendatarselamasehari, sebulanatausetahun, ygdigunakanuntmenyatakancurahanhatrian, bulananatautahunan

8. Kedalamanperakaran Soil water stored in deep layers can be used by the plants only when roots penetrate to that depth. The depth of root penetration is primarily dependent on the type of crop, but also on the type of soil. The thicker the rootzone, the more water available to the plant.

9. HUJAN: Curahan berupa air semua ukuran, baik yg berbentuk tetes yg bergaris tengah lebih dari 0.5 mm maupun yg lebih kecil (rain) HUJAN es: Curahan berupa bola kecil atau butiran es yg bergaris tengah antara 5 dan 50 mm, kadang-kadang lebih, jatuhnya secara terpisah-pisah atau bergabung menjadi gumpalan yg bentuknya tak teratur (hail)

10. In other words, the effective rainfall (8) is the total rainfall (1) minus runoff (4) minus evaporation (5) and minus deep percolation (7); only the water retained in the root zone (8) can be used by the plants, and represents what is called the effective part of the rainwater. effective The term rainfall is used to define this fraction of the total amount of rainwater useful for meeting the water need of the crops. Effective rainfall (8) = (1) - (4) - (5) - (7) www.fao.org/docrep/r4082e/r4082e05.htm

11. Shift in Thinking is Needed from Blue Water to Green Water Under the pressures of population growth, development aspirations and a growing knowledge of the importance of ecosystem support and services, water is increasingly understood as a key factor in socio-economic development. This will require a broadening of the global water debate from its current concentration on managing blue water resources in rivers, lakes and aquifers, and its current focus on the provision of potable water, the financing of such provision, and whether more water for irrigation can solve the world’s food challenge.

12. Green water is a significant water resource, much larger volume-wise than the water replenishing streams, lakes and aquifers (blue water).

13. A conceptual breakthrough that allowed an integrated land-water approach came at a UN Food and Agriculture Organization seminar in January 1993, when the concept of green water was proposed for soil moisture . According to this concept, rainfall constitutes the basic water resource and is partitioned between “green” water, which is consumed by vegetation, and “blue” water, which constitutes water in rivers and aquifers, accessible for societal use. Green water is important to terrestrial ecosystems. It is involved in (rainfed) plant production and, therefore, in the production of food, fuelwood, biofuels, timber, and forests. Because changes in plant cover alter the partitioning between green and blue water resources, this plant cover change is a key phenomenon in deforestation and reforestation. Blue water, on the other hand, is the base for the household, municipality, industry, and irrigated agriculture water supply; a carrier of solutes and silt through the water systems; and the habitat for aquatic ecosystems.

14. GREEN = BLUE BALANCE

15. The reality of the big picture is that in a drainage basin perspective, the rainfall over an area is the water resource. Part of the water is consumed in terrestrial ecosystems by vegetation and evaporation from moist surfaces (green water fl ow), while the surplus recharges aquifers and rivers (blue water) becoming available for societal use and aquatic ecosystems. Naturally, indicated, the green-blue balance is determined by the local hydroclimate.

16. GREEN WATER MANAGEMENT The water necessary to produce the food required for an expanding human population is usually discussed only as an issue of blue water for irrigation (the water we use from rivers and quifers). Most food production is from rain fed farming. This is critical not least in hunger and poverty stricken areas with rapid population growth, areas that depend not on blue water but on green water from infi ltrated rain (the soil moistures used by plants and returned as vapour flow). A shift in water thinking which considers soil moisture is essential in order to find realistic and sustainable options to feed the world of tomorrow.

17. Rain is the global water resource. How well we capture and manage it will determine if we can feed the planet’s 9 billion inhabitants by 2050. Blue water is the liquid water in rivers and aquifers. The narrow focus on blue water as the only water resource leads us to believe that agriculture uses 70% of the world’s freshwater, industry 20% and domestic use 10%. In reality, this is not the case. Green water is the soil moisture, exhaled during plant growth as vapour flow from land to the atmosphere.

18. A sustainable water future needs to incorporate the green water-consuming systems, which are generally much larger and which provide life support to humans and nature. The bulk of future freshwater needs for food production will have to come from green water management. This will affect downstream water availability. Of the world’s poor, 70% live in rural areas and often depend on rainfall-based sources of income.

19. The planet will need an additional 5,600 km3/yr of water to feed itself by 2050. The most optimistic irrigation projections show that no more than 800 km3/yr could be contributed by blue water by expansion and effi ciency improvement of irrigation. Climate change is a strong driving force for lessening society’s large-scale dependence on fossil fuels through increased use of renewable energy, though such a move will increase consumptive water use for biomass-based fuel alternatives. The future conflicts of interest will be over land use-water use, water quantity-quality, upstream-downstream availability, and humans-ecosystems.

20. A sustainable water future needs to incorporate the water from infiltrated rain and the water-consuming vegetation systems which provide life support to humans and nature: Water is of central importance in other sectors: industry production, forestry and fibre production, fisheries, etc. Huge amounts of water are needed to feed humanity, and today nearly three time more water is used in rain fed agriculture than in irrigated agriculture, with a total global consumption of 7,000 km3/year. In short, 50 to 100 times more water is needed to produce food for one person than the amount needed on a household domestic consumption level. Upstream land use and water management determines the volumes, patterns of fl ow and quality of water for downstream use, making upstream land use for forestry, rainfed farming and grazing (all of which consumes freshwater) a determinant of blue water availability downstream.

21. A sustainable water future needs to incorporate the water from infiltrated rain and the water-consuming vegetation systems which provide life support to humans and nature: Huge volumes of blue water fl ows are required to sustain aquatic ecological functions in rivers, lakes, riparian zones and estuaries. Water supply for various sectors of society is getting increasingly complicated as water contamination escalates, and awareness grows among water users of the links between upstream polluters of water with downstream water users. The largest freshwater consumption is required to sustain biomass growth in terrestrial ecosystems, supporting key ecological functions such as biodiversity, carbon sequestration and anti-desertifi cation.

22. Key Recommendations 1. Raise awareness of the distinction between blue water in rivers and aquifers and green water in the soil. 2. Accept in scientifi c, management, political and other circles the fundamental fact that there is not enoughblue water left to meet competing food, water and environment needs for the future in large regions. 3. At the same time realise that proper management of the green water in the soil represents a large potential for global food production. 4. Analyse the linkages between global trade regimes and different strategies to attain national food security. 5. Introduce a green water dimension and incorporate land-use into IWRM and adequate governance activities. 6. Further clarify the linkages between global poverty, hunger and shortage of green and/or blue water. 7. Raise awareness of the improvements possible in the livelihoods of communities – particularly those in water-scarce regions – through a broadened approach to water. 8. Further clarify the linkages between rain fed agriculture and both green and blue water.

23. Integrated Water Resources Management Integrated Water Resources Management (IWRM) has been defined by the Technical Committee of the Global Water Partnership (GWP) as "a process which promotes the coordinated development and management of water, land and related resources, in order to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems." IWRM approaches involve applying knowledge from various disciplines as well as the insights from diverse stakeholders to devise and implement efficient, equitable and sustainable solutions to water and development problems.

24. Integrated Water Resources Management IWRM is a comprehensive, participatory planning and implementation tool for managing and developing water resources in a way that balances social and economic needs, and that ensures the protection of ecosystems for future generations. Water’s many different uses—for agriculture, for healthy ecosystems, for people and livelihoods—demands coordinated action. An IWRM approach is an open, flexible process, bringing together decision-makers across the various sectors that impact water resources, and bringing all stakeholders to the table to set policy and make sound, balanced decisions in response to specific water challenges faced.

25. It has been agreed to consider water as an 'finite and economic commodity , in order to emphasize on its scarcity in the : • Fresh water is a finite and vulnerable resource, essential to sustain life, development and the environment. • Water development and management should be based on a participatory approach, involving users, planners and policy makers at all levels. • Women play a central part in the provision, management and safeguarding of water. • Water has an economic value in all its competing uses and should be recognized as an economic good, taking into account of affordability and equity criteria.

26. Green and blue water flow domains for human life support, distinguished in direct functions (direct social and economic support) and indirect functions (water for ecosystem support).

27. SumberDaya Air (SDA)  mempunyaisifatmengalirdandinamissertaberinteraksidengansistemsumberdaya lain dariberbagaisektordenganberbagaikepentingandariparapemilikkepentingansehinggamembentuksuatusistem yang disebutsistemwilayahsungai yang takjarangsangatkompleks, contohnyasajasistemwilayahsungaiBrantas.

28. DAS adalah kesatuan terkecil dari pengelolaan air, aspek pengelolaannya meliputi: Daerah tangkapan hujan Kuantitas air Kualitas air Pengendalian banjir Jasa Lingkungan DAS Prasarana pengairan

29. CALCULATING A MONTHLY WATER BUDGET

30. NERACA AIR: Keseimbangan air masuk dan air ke luar di suatu daerah hidrologi yg ditetapkan, misalnya cekungan, danau, dan lainnya, dengan diperhitungkan bahwa tempat menyimpan tidak berubah (water balance)

32. Infiltrasi dari segi hidrologi penting, karena hal ini menandai peralihan dari air permukaan yang bergerak cepat ke air tanah yang bergerak lambat dan air tanah. Kapasitas infiltrasi suatu tanah dipengaruhi oleh sifat-sifat fisiknya dan derajat kemampatannya, kandungan air dan permebilitas lapisan bawah permukaan, nisbi air, dan iklim mikro tanah. Air yang berinfiltrasi pada sutu tanah hutan karena pengaruh gravitasi dan daya tarik kapiler atau disebabkan juga oleh tekanan dari pukulan air hujan pada permukaan tanah

33. Ada 2 faktor pengaruh utama infiltrasi air hujan yaitu : Faktor yang mempengaruhi air untuk tinggal di suatu tempat sehingga air mendapat kesempatan untuk berinfiltrasi. Faktor yang mempengaruhi proses masuknya air ke dalam tanah.

34. Sprinkler Irrigation Many types micro-sprinklers, solid set, aluminum pipe a. Advantages: use less water, more precise amounts of water can be applied, less run off (tail water), may be used on slightly hilly land b. Disadvantages: expensive (installation, labor, filters, maintenance), salt buildup

35. KANDUNGAN AIR DAN TEGANGAN KURVA ENERGI - LENGAS TANAH Tegangan air menurun secara gradual dengan meningkatnya kadar air tanah. Tanah liat menahan air lebih banyak dibanding tanah pasir pada nilai tegangan air yang sama Tanah yang Strukturnya baik mempunyai total pori lebih banyak, shg mampu menahan air lebih banyak Pori medium dan mikro lebih kuat menahan air dp pori makro Tegangan air tanah, Bar 10.000 Liat Lempung Pasir 0.01 10 Kadar air tanah, % 70

36. Soil moisture content The soil moisture content indicates the amount of water present in the soil. It is commonly expressed as the amount of water (in mm of water depth) present in a depth of one metre of soil. For example: when an amount of water (in mm of water depth) of 150 mm is present in a depth of one metre of soil, the soil moisture content is 150 mm/m

37. A very general and simplified soil profile can be described as follows: • The plough layer (20 to 30 cm thick): is rich in organic matter and contains many live roots. This layer is subject to land preparation (e.g. ploughing, harrowing etc.) and often has a dark colour (brown to black). • b. The deep plough layer: contains much less organic matter and live roots. This layer is hardly affected by normal land preparation activities. The colour is lighter, often grey, and sometimes mottled with yellowish or reddish spots. • c. The subsoil layer: hardly any organic matter or live roots are to be found. This layer is not very important for plant growth as only a few roots will reach it. • d. The parent rock layer: consists of rock, from the degradation of which the soil was formed. This rock is sometimes called parent material.

38. Gerakan Air Tanah Tidak Jenuh Gerakan tidak jenuh = gejala kapilaritas = air bergerak dari muka air tanah ke atas melalui pori mikro. Gaya adhesi dan kohesi bekerja aktif pada kolom air (dalam pri mikro), ujung kolom air berbentuk cekung. Perbedaan tegangan air tanah akan menentukan arah gerakan air tanah secara tidak jenuh. Air bergerak dari daerah dengan tegangan rendah (kadar air tinggi) ke daerah yang tegangannya tinggi (kadar air rendah, kering). Gerakan air ini dapat terjadi ke segala arah dan berlangsung secara terus-menerus. Pelapisan tanah berpengaruh terhadap gerakan air tanah. Lapisan keras atau lapisan kedap air memperlambat gerakan air Lapisan berpasir menjadi penghalang bagi gerakan air dari lapisan yg bertekstur halus. Gerakan air dlm lapisan berpasir sgt lambat pd tegangan

39. Gerakan Jenuh (Perkolasi) Air hujan dan irigasi memasuki tanah, menggantikan udara dalam pori makro - medium - mikro. Selanjutnya air bergerak ke bawah melalui proses gerakan jenuh dibawah pengaruh gaya gravitasi dan kapiler. Gerakan air jenuh ke arah bawah ini berlangsung terus selama cukup air dan tidak ada lapisan penghalang Lempung berpasir Lempung berliat cm 0 15 mnt 4 jam 30 60 90 1 jam 24 jam 120 24 jam 48 jam 150 30 cm 60 cm Jarak dari tengah-tengah saluran, cm

40. Part of the water applied to the soil surface drains below the rootzone and feeds deeper soil layers which are permanently saturated; the top of the saturated layer is called groundwater table or sometimes just water table

41. A perched groundwater layer can be found on top of an impermeable layer rather close to the surface (20 to 100 cm). It covers usually a limited area. The top of the perched water layer is called the perched groundwater table. The impermeable layer separates the perched groundwater layer from the more deeply located groundwater table

42. PERKOLASI Jumlah air perkolasi Faktor yg berpengaruh: 1. Jumlah air yang ditambahkan 2. Kemampuan infiltrasi permukaan tanah 3. Daya hantar air horison tanah 4. Jumlah air yg ditahan profil tanah pd kondisi kapasitas lapang Keempat faktor di atas ditentukan oleh struktur dan tekstur tanah Tanah berpasir punya kapasitas ilfiltrasi dan daya hantar air sangat tinggi, kemampuan menahan air rendah, shg perkolasinya mudah dan cepat Tanah tekstur halus, umumnya perkolasinya rendah dan sangat beragam; faktor lain yg berpengaruh: 1. Bahan liat koloidal dpt menyumbat pori mikro & medium 2. Liat tipe 2:1 yang mengembang-mengkerut sangat berperan

43. LAJU GERAKAN AIR TANAH Kecepatan gerakan air dlm tanah dipengaruhi oleh dua faktor: 1. Daya dari air yang bergerak 2. Hantaran hidraulik = Hantaran kapiler = daya hantar i = k.f dimana i = volume air yang bergerak; f = daya air yg bergerak dan k = konstante. Daya air yg bergerak = daya penggerak, ditentukan oleh dua faktor: 1. Gaya gravitasi, berpengaruh thd gerak ke bawah 2. Selisih tegangan air tanah, ke semua arah Gerakan air semakin cepat kalau perbedaan tegangan semakin tinggi. Hantaran hidraulik ditentukan oleh bbrp faktor: 1. Ukuran pori tanah 2. Besarnya tegangan untuk menahan air Pada gerakan jenuh, tegangan airnya rendah, shg hantaran hidraulik berbanding lurus dengan ukuran pori Pd tanah pasir, penurunan daya hantar lebih jelas kalau terjadi penurunan kandungan air tanah Lapisan pasir dlm profil tanah akan menjadi penghalang gerakan air tidak jenuh

44. RETENSI AIR TANAH KAPASITAS RETENSI MAKSIMUM adalah: Kondisi tanah pada saat semua pori terisi penuh air, tanah jenuh air, dan tegangan matrik adalah nol. KAPASITAS LAPANG: air telah meninggalkan pori makro, mori makro berisi udara, pori mikro masih berisi air; tegangan matrik 0.1 - 0.2 bar; pergerakan air terjadi pd pori mikro/ kapiler KOEFISIEN LAYU: siang hari tanaman layu dan malam hari segar kembali, lama-lama tanaman layu siang dan malam; tegangan matrik 15 bar. Air tanah hanya mengisi pori mikro yang terkecil saja, sebagian besar air tidak tersedia bagi tanaman. Titik layu permanen, bila tanaman tidak dapat segar kembali KOEFISIEN HIGROSKOPIS Molekul air terikat pada permukaan partikel koloid tanah, terikat kuat sehingga tidak berupa cairan, dan hanya dapat bergerak dlm bentuk uap air, tegangan matrik-nya sekitar 31 bar. Tanah yg kaya bahan koloid akan mampu menahan air higroskopis lebih banyak dp tanah yg miskin bahan koloidal.

45. Status Air Tanah Perubahan status air dalam tanah, mulai dari kondisi jenuh hingga titik layu Jenuh Kap. Lapang Titik layu Padatan Pori 100g air 40g tanah jenuh air 100g 20g udara kapasitas lapang 100g 10 g udara koefisien layu 100g 8g udara koefisien higroskopis

46. Agihan air dalam tanah Berdasarkan tegangan air tanah dapat dibedakan menjadi tiga bagian: Air bebas, kapiler dan higroskopis Koef. Higroskopis Kap. Lapang Jml ruang pori kurang lebih 31 atm kurang lebih 1/3 atm Lapisan olah Air higros- Air Kapiler Ruang diisi udara kopik Peka thd gerakan Biasanya jenuh uap air Hampir tdk kapiler, laju pe- Setelah hujan lebat menunjukkan nyesuaian me- sebagian diisi air, sifat cairan ningkat dg me- tetapi air cepat hi- ningkatnya ke- lang krn gravitasi lembaban tanah bumi Lapisan bawah tanah Karena pemadatan ruang pori berkurang Strata bawah (jenuh air) Kolom tanah Jumlah ruang pori

47. Soil water • infiltration & percolation • permeability • porosity • zone of aeration • soil water storage • plant uptake & transpiration • evaporation • throughflow • water table • zone of saturation • groundwater flow • aquifer

48. SUPLAI AIR ke TANAMAN Dua proses yg memungkinkan akar tanaman mampu menyerap air dlm jumlah banyak, yaitu: 1. Gerakan kapiler air tanah mendekati permukaan akar penyerap 2. Pertumbuhan akar ke arah zone tanah yang mengandung air LAJU GERAKAN KAPILER Bulu akar menyerap air Tegangan air tanah meningkat Jumlah air tanah berkurang Terjadi perbedaan Tegangan dg air tanah di sekitarnya Terjadi gerakan kapiler air menuju bulu akar Laju gerakan tgt perbedaan tegangan dan daya hantar pori tanah Gerakan kapiler 2.5 cm sagt penting LAJU PERPANJANGAN AKAR Selama masa pertumbuhan tanaman, akar tanaman tumbuh memanjang dengan cepat, sehingga luas permukaan akar juga tumbuh terus. Jumlah luas permukaan akar penyerap yang bersentuhan langsung dengan sebagian kecil air tanah (yaitu sekitar 1-2%)

49. KEHILANGAN UAP AIR DARI TANAH HADANGAN HUJAN OLEH TUMBUHAN Tajuk tumbuhan mampu menangkap sejumlah air hujan, sebagian air ini diuapkan kembali ke atmosfer. Vegetasi hutan di daerah iklim basah mampu menguapkan kembali air hujan yg ditangkapnya hingga 25%, dan hanya 5% yg mencapai tanah melalui cabang dan batangnya. Awan hujan Pembentukan Awan presipitasi transpirasi evaporasi Run off infiltrasi Tanah permukaan perkolasi Sungai - laut Groundwater Batuan

50. Hadangan hujan oleh tanaman semusim Sekitar 5 - 25% dari curah hujan dihadang tanaman dan dikembalikan ke atmosfer. Besarnya tergantung pada kesuburan tanaman dan stadia pertumbuhan tanaman . Dari curah hujan 375 mm, hanya sekitar 300-350 mm yang mencapai tanah. Hadangan curah hujan oleh jagung dan kedelai Keadaan hujan Persen dari curah hujan total untuk: Jagung Kedelai Langsung ke tanah 70.3 65.0 Melalui batang 22.8 20.4 Jumlah di tanah 93.1 85.4 Yang tinggal di atmosfer 6.9 14.6 Sumber: J.L.Haynes, 1940.