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1 Bahan Kajian MK. PSDALH Smno.psdl.pdkl.ppsub.nop2013 MANAJEMEN AIR HUJAN RAIN-GARDEN TAMAN HUJAN.

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Presentasi berjudul: "1 Bahan Kajian MK. PSDALH Smno.psdl.pdkl.ppsub.nop2013 MANAJEMEN AIR HUJAN RAIN-GARDEN TAMAN HUJAN."— Transcript presentasi:

1 1 Bahan Kajian MK. PSDALH Smno.psdl.pdkl.ppsub.nop2013 MANAJEMEN AIR HUJAN RAIN-GARDEN TAMAN HUJAN

2 Maintain & replace infrastructure 1.Infrastructure 2.In place some time 3.Pipers clog 4.Impede storm water flow 5.Open ditches gradually fill 6.Vacuum and water jet trucks 7.Replace with BMP https://www.facingthefuture.org/Curriculum/PreviewandBuyCurriculum/tabid/550/List/1/ProductID/28/Defa ult.aspx#.UpsUGCdRWho

3 Improve stream water quality 1.Streams impaired 2.Streams may not be suitable for certain aquatic life/human recreation 3.Monitoring/resea rch useful-aid in stream quality 4.BMP. Bio retention area, debris catchments, bank restoration 5.Improve water quality

4 BMP improvement 1.Restoration 2.Habitat Movement of water through a detention pond-wetlands system (Martin and Smoot, 1986)

5 What is an impervious surface? 1.Rainwater cannot infiltrate 2.More water volume-runoff into storm drain 3.Storm water fee 4.Median impervious area of single family residential propertied m2

6 What is goal of storm water fee? 1.Maintain water quality 2.Allow city to comply – federal-state regulations- unfunded mandate 3.Flood damage reduction/drai nage 4.Long term maintenance Infiltrasi permukaan dapat dicapai melalui penggunaan strip penyangga rumput, sengkedan bervegetasi, dan sistem perkerasan berpori. Sistem infiltrasi seperti parit resapan, cekungan infiltrasi, dan zone bioretention (termasuk taman hujan) yang dirancang khusus untuk menangkap volume limpasan hujan dan transfer langsung ke profil tanah. Beberapa praktik yang terintegrasi, seperti restorasi kualitas tanah dan lansekap, dapat digunakan untuk meningkatkan kapasitas infiltrasi tanah perkotaan. Sebuah fasilitas infiltrasi dirancang untuk menangkap volume limpasan air hujan, menahan, dan meresapkan seluruh atau sebagian air tersebut ke dalam tanah.

7 What is goal of storm water fee? 1.Protect water supply 2.Stream restoration 3.BMP-road construction 4.Education for schools 5.Workshops for better water quality Infiltrasi air hujan memiliki kelebihan dan kekurangan. Keuntungan dari infiltrasi mencakup pengendalian kuantitas air dan pengendalian kualitas air. Kontrol kuantitas air dapat terjadi dengan menangkap dan menahan aliran permukaan dan infiltrasi air ke dalam tanah, mengurangi volume air yang dibuang langsung ke sungai. Sistem Infiltrasi dapat dirancang untuk menangkap volume air hujan (volume & kualitas air) dan meresapkan air ini ke dalam tanah selama beberapa jam atau hari. Infiltrasi dapat memberikan manfaat sekunder dengan meningkatkan mengisi ulang akuifer dan meningkatkan aliran dasar sungai di dekatnya.

8 What can you do for clean water? 1.Conserve water 2.Keep grass clipping out of stream 3.Keep restaurant and business waste away from rain Ada beberapa praktik infiltrasi: 1.Parit infiltrasi 2.Cekungan infiltrasi 3.Daerah Bioretention (dan taman hujan) 4.Restorasi kualitas tanah asli lansekap

9 What can you do for clean water? 1.Use min herbicides/fertilizer s & keep off paved surfaces 2.Pick up pet waste 3.Report water pollution Faktor-faktor yang mengontrol laju infiltrasi dan kapasitas infiltrasi: 1.Tutupan vegetasi, perkembangan akar, dan kandungan bahan organik 2.Kadar air 3.Struktur tanah dan tekstur 4.Porositas dan permeabilitas 5.Bobot isi Tanah dan pemadatan 6.Slope, posisi landscape, dan topografi

10 Rain Garden Managejemen Air Hujan di Perkotaan

11 Apa saja yang digunakan untuk mengelola air hujan di perkotaan? 1.Gutters for roof runoff 2.Surface drainage ditches and an underground drainage system. 3.Ditches or tiles direct water to a central basin. 4.Permeable pavement …http://www.daygroup.co.uk/sustainable-urban-drainage-systems.php Typical Permeable Pavement Design

12 Permeable paving in sustainable urban drainage systems (SUDS) Paving permeabel atau porus dapat digunakan sebagai sarana kontrol limpasan air hujan di jalan-jalan kecil, trotoar, parkir mobil dan taman- taman kota. Sarana pengendalian limpasan air hujan di perkotaan adalah sistem drainase perkotaan yang berkelanjutan (SUDS) yang berhubungan dengan run-off, dan dengan permukaan lahan tempat jatuhnya hujan. Air hujan melewati permukaan lahan, meresap melalui celah-celah di antara individu paving atau bahan permeabel seperti kerikil atau aspal porus, menjebak polutan di dalam tanah. Dalam tanah, bahan polutan akan mengalamu degradasi dan dekomposisi oleh proses alami yang terjadi dalam tanah.

13 Permeable paving in sustainable urban drainage systems (SUDS) Dengan menggunakan permeabel paving dapat dicegah akumulasi air di permukaan kedap air, menghindari genangan air di tempat parkir. Sejumlah besar air dapat disimpan dalam tanah di bawah permukaan. Hal ini mengurangi kemungkinan banjir.

14 Apa saja masalah yang dihadapi? 1.Petrochemicals and metals are washed off with storm runoff water. 2.Rain water and runoff water can dissolve the limestone bedrock. …http://www.ec.gc.ca/inre-nwri/default.asp?lang=En&n=235D11EB-1&offset=12&toc=show Linkages between urban runoff and water quality issues.

15 Dimana lokasinya Rain-garden ? 1.Rain Gardens are near the campus greenhouse (GH) 2.Rain Gardens are near the Horticulture Center (HC) 3.Rain Gardens are in the drainage ditches. …

16 Surface Drain system being retrofitted with Rain Gardens (RG) Green house Commons- underground drain line Basin RG 1 & 2 RG3 …

17 Runoff from curb cut into Rain Gardens

18 Alternative ways of dealing with runoff? 1.Direct water to a naturalized setting. 2.Minimize runoff of average rain by 90%, allowing rain garden ( plants and soil) 3.Filter pollutants- sediments, dissolved ions- before percolates into groundwater. Perbaikankualitas air hujan dapat dicapai kalau bahan polutan tersaring pada saat air hujan merembes melalui berbagai lapisan tanah. Ketika air bergerak melalui tanah, partikel dapat diikat oleh partikel tanah. Selain itu, mikroorganisme dalam tanah dapat mengurangi polutan organik yang terkandung dalam air hujan.

19 What is a decentralized runoff management system? 1.Runoff water directed into rain gardens 2.Plant canopy and soil can store excess water. 3.Rain Garden, shallow basin allows runoff water to percolate through the soil and transpire through the plants. Urban runoff source areas and drainage alternatives (Pitt 1986).

20 How does a decentralized system work? Two ways: 1) Plant canopy ( trees, shrubs, un-mowed grasses) A) increase evapo-transpiration B) reduce water percolation. 2) Rain garden soil is a sponge for runoff water …

21 Surface Drain system being retrofitted with Rain Gardens (RG) 21 Green house Commons- underground drain line Basin RG 1&2 RG3 …

22 Rain Garden Taman hujan dibangun untuk dapat menampung dan segera meresapkan limpasan air hujan tersebut ke dalam tanah. Air hujan tidak boleh terlalu menggenang di taman-hujan, hal ini untuk melindungi kesehatan tanaman yang tidak tahan genangan air.

23 Digging out Rain Garden

24 Spoil piles in background-gravel at entrance Rain Garden Kalau hujan terjadi di perkotaan yang permukaannya pedap air, maka diperlukan taman- hujan yang mampu menampung sebagian limpasan air hujan dan meresapkannya ke dalam tanah. Hal ini membantu mengurangi beban debit runoff yang memasuki saluran drainage kota.

25 Rain Garden 25 …http://www.alabamas13.com/story/ /with-all-of-this-rain-how-about-a-rain-garden Taman hujan adalah depresi (cekungan) dangkal yang ditanami dengan tanaman asli yang mengakar kuat dan/atau rumput. Taman hujan ini lokasinya sedekat mungkin dengan sumber limpasan air hujan, seperti jalan-jalan kota. Taman hujan ini akan menangkap limpasan air hujan dan menahan air ini dan meresapkannya ke dalam tanah.

26 Rain Garden 1.Deeper and longer than needed in a residential landscape 2.Why? 3.It had to fit in an existing drainage ditch surrounded by parking lots. 26 …http://soundbook.soundkeeper.org/chapter_ContentID_212_SectionID_7.htm

27 How to Plan a Rain Garden 1.Garden is down slope from the area it is draining. 2.Small rain gardens are easier to maintain than one large rain garden. 3.Garden should be greater than 10 feet from building foundation. …http://www.alabamas13.com/story/ /with-all-of-this-rain-how-about-a-rain-garden

28 Building Rain Garden : Placement 1.Rain Garden is on the East side of Horticulture Center. 2.Captures water from the graveled lot on the West side of the Horticulture Center. …http://rpitt.eng.ua.edu/Class/Computerapplications/Module4/MainCAM4.html Pollutant deposition and removal at source areas (Pitt 1986).

29 Other Placement Considerations Do not place over a septic system or where water pools more than 5 days. The garden soil should drain well. How a soil drains can be determined by watching the site after a rainfall event – Does it drain within 2 to 3 day – If not infiltration and percolation rate can be estimated. Clay soil or compacted soil can be amended to improve infiltration and percolation. …

30 What is water infiltration? 1.How quickly does water move into a soil? 2.Watch a possible area after a rain fall event. Infiltrasi mungkin tidak cocok untuk di daerah-daerah di mana air-tanah merupakan sumber utama air minum, karena potensi migrasi kontaminan. Hal ini terutama berlaku jika air limpasan berasal dari daerah komersial atau industri, di mana mungkin ada kontaminasi limbah organik atau logam.

31 What is the percolation rate? The percolation rate is the time it takes for one inch of water to pass through a soil. The ABAS class used these perc rates: <60 minutes/inch minutes/inch >75 minutes/inch A good rate for a rain garden is <60 minutes per inch. …

32 How to determine percolation rate by soil texture? Using a post hole digger, dug holes 6 to 8 inches for a shallow basin or 24 to 36 inches for a deep basin. For faster than 60 minutes per inch – Excavate soil has a medium or fine textures subsoil – Or fine reddish textured subsoil …

33 How to determine percolation rate by soil texture? For 60 to 75 minutes per hour – Excavated soil is reddish fine textured subsoil to at least 24 inches and yellow clay between 24 to 36 For slower than 75 minutes per inch – Excavate soil with bed rock within 36 inches – or soil having a yellowish, grayish, or blackish fine textured subsoil …

34 Uji Rasa untuk Tekstur Tanah 1.Fine texture soils: Sandy clay, Silty clay and clay 2.Medium texture soils: silt loam, loam, sandy clay loam, clay loam, silty clay loam …

35 35

36 Rain Garden: Ruang sempit … Air hujan mencuci polutan di sepanjang jalan dan memasuki taman-hujan Air hujan menyebar ke seluruh permukaan taman-hujan dan vegetasi menangkap sedimen kasar Air hujan yang bersih dikumpulkan dalam pipa dan disalurkan ke perairan bebas Air hujan meresap ke bawah melalui massa tanah, sedimen halus dan polutan ditangkap oleh tanah

37 Building Rain Garden : Laju Perkolasi 1.Dug holes to 24 inches, excavated soil in the proposed Rain Garden, was medium textured. 2.1” gravel in bottom, filled holes with 6” of water and record time to drop one inch. Stuck a tooth pick in the side of the hole for measuring water drop. 3.Measured, 15 minutes per ¼” water drop, or 60 minutes per 1” water. …

38 Building Rain Garden: Sizing? The size of the rain garden can be calculated. – Residential size: 100 to 300 sq ft The size required to capture surface runoff around the site was determined by observations. – E.g. Dimensions: 8 feet x 24 feet by 6 inches deep …

39 Finding the Area Rain Garden 1.If rain garden catch water from a rain spout, use that part of the roof area. 2.Lawns, graveled or paved driveways, additional runoff water for a rain garden. 3.The area to be drained can be multiplied by a size factor to determine area of rain garden. …

40 Size factors are determined according to the type of soil and the depth of the garden and differ if the garden is 30’ from a building <30 Feet 3-5” deep 6-7” deep 8” deep Sandy Soil Silty Soil Clayey Soil >30 feet For all depths Sandy Soil0.03 Silty Soil0.06 Clayey Soil0.10

41 % Slope Relates to the Depth of the Rain Garden 1.For slopes <4%, the garden depth should be 3-5 inches deep. 2.Between 5-7%: 6 to 7 inches deep 3.Between 8-12%: about 8 inches deep 4.For slopes over 12%, a rain garden will take a great deal of fill, another location should be considered. …

42 Calculating the Slope & Area of the Rain Garden 1.Drive two stakes about fifteen feet from each other (one uphill, one downhill). 2.Tie a string level to each stake and adjust it to make it level. 3.Measure height difference between the ground and the string in feet, divide difference by the distance between the two stakes. 4.Multiply by 100 to get the percent slope. …

43 Defining the Shape of the Rain Garden 1.Shape should be aesthetic. 2.Recommend, length of the garden be perpendicular to the slope, will catch as much water as possible. 3.Garden should be twice as long as it is wide. 4.Width should be no more than feet. …

44 Building Rain Garden: Digging 1.Mark the perimeter of the garden. 2.Front end loader was initially used; for residential garden use a garden tiller. 3.District conservationist showed the class how to measure slope with a laser level. It is easy to do with a string and line level. 4.The inlet was higher than the outlet and the bottom of the garden was leveled. …

45 Digging a Rain Garden 1.Hammered stakes around the perimeter and ran string level between stakes across the middle of the garden. 2.Dig the bed level at the desired depth with rakes and shovels. 3.Use the removed soil to build a berm on the downhill edge of the garden. 4.Covered channel above and below inlet and outlet with landscape fabric and gravel …

46 Building Rain Garden : Planting 1.The Soil Analysis class planted native bushes and perennials. 2.The arrangement was done in a naturalistic fashion using odd number groups. 3.Odd number groups ease future maintenance of the Rain Garden. …

47 Planting a Rain Garden 1.Rain garden plants should be tolerant of moist and dry conditions. 2.Commercial landscape plants can be used but consider native plants. 3.Plant density should be higher and more naturalistic looking than commercial type plantings. …

48 Building Rain Garden : Mulch and Rock 1.Placed landscape fabric at the entrance of the Rain Garden. 2.Covered the bottom of the Rain Garden with double-shredded mulch to the desired depth. 3.Covered the landscape fabric at the entrance with river rock. …

49 Rain Garden Sebuah taman hujan dengan vegetasi di daerah perkotaan dapat memperbaiki kualitas air dan kenyamanan lingkungan sekitarnya.

50 Rain Garden - Specs Infiltration Rate – 3 inches in 90 minutes Depth – 7 inches Materials Used – river rock, landscape fabric, recycled concrete (from construction site on campus), native plants. …

51 Plants Used 1.River Oats - Chasmanthium latifolium 2.Swamp Milkweed – Ascelpias incrnata 3.Red Twig Dogwood - Cornus sericea 4.False Sunflower – Heliopsis helianthoides 5.Helberd Leaf Rose Mallow – Hibiscus laevis 6.Inkberry Holly – Ilex glabra 7.Winterberry Holly – Ilex verticillata 8.Big Blue Lobelia – Lobelia siphilitica 9.Common Rush - Juncus effusus

52 Construction of Rain Garden - after Excavation Tanah di taman hujan harus longgar dan porous, sehingga kemungkinan tanah perlu diplah sebelum penanaman tanaman. Penambahan Kompos organik, pasir, vermiculite, dan material tanah liat ke tanah aslinya dapat memperbaiki kualitas tanah di taman-hujan.

53 Landscape Fabric Although fabric is beneficial to prevent weeds, it does not allow the rock to settle. Notice how the fabric and rock washed away due to heavy rain.

54 Landscape Fabric Correction We corrected the problem with recycled concrete and rocks to hold the fabric in place and to slow down the water flow.

55 Rain Garden: lime dust on river rock … Agar supaya taman-hujan dapat bekerja dnegan sebaik-baiknya, lokasinya harus di tempat dimana limpasan air hujan mengumpul, atau saluran air drainage. Untuk memilih tempat terbaik (jika ada pilihan), diperlukan pengamatan lapangan setelah hujan lebat.

56 In Summary 1.Environmental problems caused by surface drainage in developed areas can be reduced by changing landscape practices. 2.Limit mowed lawn space and raise mower blade to increases plant canopy. 3.Stacked Rain gardens in the landscape allow excess water to infiltrate the soil in many places before water flows to lowest elevation. …

57 Plant Lists Plant lists will be available on request from: 1. your local extension office 2. Tennessee Master Gardeners 3. web search: rain garden plants …

58 Rain Garden Vegetasi di taman-hujan harus dapat beradaptasi dengan kondisi tanah basah dan tanah kering. Tanaman asli biasanya sangat cocok untuk taman- hujan, karena mereka mampu beradaptasi terhadap kondisi lokal. Tanaman yang cocok untuk taman-hujan akan bervariasi dari satu daerah dengan daerah lainnya.

59 Entrance to Rain Garden … Taman hujan dengan tanaman asli, di kawasan permukiman, dapat mengurangi jumlah polutan yang memasuki badan air terdekat atau saluran drainage kota. Taman hujan juga dapat mencegah erosi permukaan, dapat mengurangi genangan air, dan menciptakan habitat bagi satwa liar, seperti burung. Taman hujan dapat diintegrasikan dnegan Ruang Terbuka Hijau Kota.

60 Rain Garden …http://www.alabamas13.com/story/ /with-all-of-this-rain-how-about-a-rain-garden Ada banyak pohon-pohon dan semak-semak yang cocok untuk taman-hujan, namun sebagian besar tumbuhan ini ukurannya terlalu besar untuk menjadi bagian dari sebuah taman-hujan yang kecil. Dengan tanaman yang lebih kecil, dan media tanah yang bagus, taman-hujan kecil di ruang perkotaan dapat menjadi sarana keindahan kota dan kenyamanan ekologis lingkungan kota.

61 Fact sheet- Rain Garden Design(2) Who Should Create a Rain Garden? 1.Suitable any land use; Residential, commercial, industrial 2.Place so impervious surfaces drain into depression 3.Grass buffer strip 4.Slows water entering rain garden; Surface filters particulates from runoff 5.Pond area 6.Depression area, stores water; Evaporation; Particulate not filtered to settle to bottom; 7.6 inch depth; Not pond more than 3-4 days – avoid mosquito breeding

62 Fact sheet- Rain Garden Design(4) Components of a rain garden 1.Mulch/Organic Layer 2.Decomposed organic material; Removes metals; Shredded hardwood mulch 3.Planting Soil 4.Leaf mulch (20%), sandy soil (50%) and 30% top soil; Clay particles adsorb 5.Planting Selection 6.Species that tolerate extremes, perennials 7.Site Considerations 8.Site: Intercept water runoff 9.Bioretention area: 5 to 7% of drainage area (example ¼ roof area)


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