SYAHERMANAA990522DO3TT1

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Saya akui karya ini adalah hasil kerja saya sendiri kecuali nukilan dan ringkasan

yang tiap-tiap satunya telah saya jelaskan sumbernya.

Tandatangan : ..

Nama Penulis : ..

Tarikh : ..


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PENGHARGAAN

Assalamualaikumwarahmatullahiwabarakatuh...

Alhamdulillah , dengan rasa sukacitanya saya ingin mengucapkan syukur ke hadrat

Illahi kerana dengan limpah dan kurnia-Nya, maka Projek Sarjana Muda ini dapatdisiapkan dengan sempurna. Di kesempatan ini saya ingin merakamkan setinggi-tinggi

penghargaan kepada penyelia saya, iaitu Prof. Dr. Noraeini Hj. Mokhtar yang telah

banyak membantu dan memberi tunjuk ajar kepada saya menyiapkan laporan projek

pada semester 2002/2003 ini.

Ribuan terima kasih juga kepada rakan-rakan seperjuangan terutamanya saudara

Syaiful Marzuki , Suhairi dan Irwan Petra , yang sering membantu dalam memberi

pendapat, cadangan dan komen di samping dorongan yang mereka berikan.

Jutaan terima kasih ingin saya ucapkan kepada mereka yang banyak memberi

dorongan dan galakan kepada saya selama ini terutamanya emak, ayah serta ahli keluarga

saya.

Tidak ketinggalan juga kepada semua yang terlibat dalam penyiapan laporan

projek ini. Jika bukan kerana bantuan dan sokongan anda semua, maka syarat-syarat

kelayakan untuk menyiapkan Projek Sarjana Muda ini mustahil untuk dicapai.

Syaherman bin Johar,

Mac 2003.


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Buat insan yang tersayang ~ Emak dan Ayah yang dikasihi, kasih sayang, bimbingan,

pengorbanan dan jasamu abadi selamanya..

Untuk yang teristimewa ~ Norul Aizan Mohd Hanafi , jutaan terima kasih yang

tidak terhingga atas segala galakan dan dorongan serta doa yang tidak putus-putus

sehingga berjaya sampai ke peringkat ini...

Tidak lupa juga buat teman-teman serumah dan rakan-rakan seperjuangan..


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ABSTRACT

River bank erosion can present serious problems to river engineers, environmental

managers and farmers through loss of agricultural land, danger to riparian and floodplain

structures, increase downstream sedimentation, and occasional riverine boundary

disputes. Construction and management details are important to successful control of erosion and sediment. Nowadays, the technology for erosion and sediment control is well

developed. The problem is to apply the technology correctly and thereby control the

problem at its source. Improper design and installation often results in problems more

severe than those that were to be avoided. Since there are many kind of methods that can

prevents erosion, it is desirable to select the most effectively control measure to get a best

results of solution for rectification and stabilization of river banks. Besides, when the

measures were been choose, erosion will successful controlled without caused to both

environmental and economic impacts. In this research, there is a solution for rectification

of river banks by using a selected and modern techniques. Besides, a suitable

management also needed to result a proper installation while doing a construction

activities.


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CONSTRUCTION TECHNIQUES AND MANAGEMENT OF ECO-ENGINEERING SOLUTION FOR RECTIFICATION OF RIVER

BANKS.

Noraieni Hj. Mokhtar, PhD 1 , Syaherman Johar ,Bsc 21Faculty of Civil Engineering, Universiti Teknologi Malaysia2Faculty of Civil Engineering, Universiti Teknologi Malaysia

Abstract : River banks erosion can present serious problems to river engineers,environmental managers and farmers through loss of agricultural land, danger toriparian and floodplain structures, increase downstream sedimentation, andoccasional riverine boundary disputes. Design and construction details are vitallyimportant to successful control of erosion and sediment. Nowadays, thetechnology for erosion and sediment control is well developed. The problem is toapply the technology correctly and thereby control the problem at its source.Improper design and installed often results in problems more severe than thosethat were to be avoided.

Keywords: design and construction, river bank, erosion.

1. INTRODUCTION

Vegetation is one of methods used to control erosion for rectification and stabilization of river bank. Experience the numerous rivers indicates that vegetation is ineffective in

protecting river banks from erosion except at the water surface-bank interface. Grassesand shrubs help protect banks against erosion from wave action, surface velocities, andsmall variations in flow elevation in the vicinity of the water surface. Vegetation is themost cost-effective form of erosion control. It is also self-healing and attractive. Sincevegetation prevents erosion, it is a more desirable control measure than straw bale dikes,silt fences, and sediment traps and basins. Vegetation reduces erosion by absorbing theimpact of rain drops, reducing the velocity of runoff, reducing runoff volumes byincreasing water percolation into the soil, binding soil with roots and protecting soil fromthe wind.

2. SITE PREPARATION

Construction practices, such as extensive clearing and earth moving, procedure largeareas of exposed soil with a high potential for erosion. Grading creates cut and fill areasthat have soil conditions substantially different from the original ones. Cut slopes aretypically stripped down to the subsoil or parent material (rock). The exposed slope isoften hard, rocky, and low in fertility. Initial plant regrowth on such slopes will probably

be scraggly and thin. Fill areas generally contain a mixture of topsoil, subsoil, rock andanything else that had to be disposed of. A common fill material may be the gradingspoils from the other construction projects. Thus, a fill area may contain the right types of


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soil for plant growth, but they are often mixed up or inverted or may not have originatedat the site. The unpredictable soil composition and potential for differential compactionand settling make fill areas particularly susceptible to erosion.

Before a disturbed site is revegetated, the earth should be shaped and roughened to create

a favorable environment for plants to grow in. it is a common practice to grade slopesuntil they have a hard, smooth surface. Such slopes give false give a false impression of finished grading and a job well done. Seedling roots have a difficult time penetratingthese surfaces. A light rain or wind can easily carry away the seeds.

3. FIELD WORK

3.1 SEEDING

The key factor of seeding is to get the seeds evenly distributed and in contact with the

soil. Best results are obtained when seeds are covered with shallow layer of soil to adepth of to inch (0.6 to 1.3 cm). It should not have a soil cover greater than 1 inch(2.5 cm). Seeding can be done by hand, by machine (seed drill), by hydraulic jet, or byaircraft. The steepness of slope and size of area determine the proper equipment to use.Hand broadcast seeding is effectively seeded at small, gently sloping or flat areas. Breastseeders (belly-grinders) are inexpensive. Seed can be covered by lightly raking the soilor by dragging a chain over the surface. The seed may become covered naturally on arough, loose seedbed. Hydraulic seeding and mulching (hydroseeding) is the mostefficient means for seeding steep slopes. It is a one-step process for spraying a slurry of seed, fertilizer, wood fiber mulch, and water. The critical factor in hydroseeding is theability of the fiber to adhere to the soil and hold the seed in place during rainfall andwind. Seed drills are commonly used in agriculture. They can be used only on flat or gently sloping sites. Because seed drills plat seeds at the proper depth, they provide the

best stands of grass. In addition, when seed is drilled, seed and fertilizer rates may be cutin half.

3.2 FERTILIZER

Fertilizer is essential to the establishment of vegetation, particularly on cut slopes. Theamount and composition of fertilizer to use depends on local soil conditions. As wasstated earlier, it is preferable to use plants that can survive without repeated fertilization.Fertilizing is costly, and on most sites you cannot count on having someone there to do ityear after year. Excessive fertilizer can cause water pollution. However, on sites withsandy or coarse-grained soils, such as decomposed granite, reapplication of fertilizer may

be necessary for continued plant cover.


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3.3 MULCHING

Application of mulch protects a disturbed site from erosive forces until plants are largeenough to do the job. Mulch materials include straw, wood fiber, wood chips, bark, fabricor plastic mats, soil and gravel.

3.3.1 Straw Mulch

Straw mulch is highly effective at absorbing raindrop impact and moderating theclimate on the soil surface. Straw mulch should not be applied too heavily. Soilshould be visible through the straw mat. Straw can be applied either by hand or by

blower. It is difficult to apply straw uphill or under windy conditions. Straw must be anchored to keep it from blowing away. Common methods of holding straw in place includes crimping, disking, rolling or punching it into the soil, covering itwith netting and spraying with a chemical or fiber binder. Those methods arecommonly accomplished with commercial machine called sheepsfoot roller.

3.3.2 Wood Fiber Mulch

Wood fiber mulch consists of fine wood fibers to which a green dye added tomake the mulch visible on the ground when it is being applied. It is easy to applywith a hydroseeder. Instead, wood fiber mulch does not by itself provide mucherosion protection. This is because it does no have enough mass to absorb theenergy of raindrops and flowing water. Typically, wood fiber is appliedhydraulically which is wood fiber, seed, fertilizer, and water are combined in atank and applied together as a slurry.

3.3.3 Nettings

Heavy-weight netting materials such as jute (woven fibers) and excelsior can beeffective mulches. Not only do these dense nettings hold soil in place but alsoabsorb water and hold moisture near the soil surface. It must be so applied that isin complete contact with soil so it can be protected from erosion. Netting should

be anchored to the soil with No. 11 gauge wire staples at least 6 inch long. Onvery hard rocky soils, the netting can be anchored by using large nails andwashers. However, the materials may need a high cost.

4. TEST AND RESULT

4.1 Test Procedures

Mulches were tested on 0.6- by 1.2 meter boxes of soil inclined at 5:1 and 2:1 slopes(horizontal to vertical ratio). Rainfall was simulated by using 3-mm-diameter dropsfalling 4.5 meter at the range of 152 mm/hour for periods of 2 to 6 hour. The soil boxeswere designed to allow rapid drainage if water moved through the top 15 cm of soil. Soil


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washed from each box was collected, dried and weighed. Eight soils were used in thetests which is taken from construction sites (Table 1.0)

4.2 Test Results

Figure 1.0 shows the rate of erosion from each of the soil types when no protection wasused. Soil loss was greater from all soil types when inclined at 2:1 than at 5:1. the mosterodible soils were those with high percentages of fine sand and silt including the threeloam soils. The uncemented fine sand did not erode initially, but it would liquefy whensaturated and down downslope. On, the 2:1 slope, this liquefied sand flowed rapidly andthus produced very high erosion rate. The least erodible soils were the coarse, gravelly,decomposed granite and the soil with the highest clay content.

Table 1.0 : Textures and particle size percentages of soils used in mulch

Texture Name Clay Silt Sand Graveluncemented fine sand Arnold 2 3 95 0very gravelly coarse sand Decomposed granite 3 4 41 52gravelly sandy loam Cieneba 9 9 49 33sandy clay loam Dibble 21 18 61 0loam Los Osos 17 48 35 0loam Yolo 22 45 33 0loam Auburn-Sobrante 21 43 36 0clay loam Altamont 29 45 26 0

Figure 1.0 : Erosion rater from unprotected soil surfaces inclined at 5:1 and 2:1 slopes.


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4. CONCLUSIONS

The conclusions that can be drawn from this study are as follows:

1. Vegetation using straw mulch provided much greater protection on all soils, but particularly on the uncemented fine sand, the decomposed granite, and the clayloam.

2. The wood fiber mulch, though less effective than straw, did offer some protection.3. When an erosion control treatment is to be selected, it is necessary to consider

both short and long-term effectiveness.4. Hydraulic seeding and mulching with wood fiber does provide adequate erosion

protection if plants are established, but its pregermanation effectiveness is low tomoderate.

5. Jute netting and jute over straw are highly effective but very costly treatments andthey are best for small sites and critical areas.

5. REFERENCES

1. Association of Bay Area Governments, Manual of Standards for Erosion and Sedimentation Control Measures , ABAG, Oakland, Calif., 1981.

2. R. P. Beasley, Erosion and Sedimentation Pollution Control , The Iowa StateUniversity Press, Ames, Iowa, 1972.

3. F. W. Bennett and R. L. Donahue, Methods of Quickly Vegetating Soils of Low Productivity, Construction Activities , U. S. Environmental Protection Agency,Washington D. C., 1975.

4. Dr. Farber, Recommended Planting Time For Vegetative Stabilization of

Construction Sites, Technical Memorandum No. 51, in San Francisco Bay Area Environmental Management Plan, Appendix J , Association of Bay AreaGovernment, Oakland, Calif., 1981.

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