LOWER SOLO RIVER IMPROVEMENT PROJECT, PHASE-I
PROJECT BACKGROUND
The Solo River is the largest river in Java island. It drains a cathment area of about 16,100 km2, discharging into the Java Sea to north of the Surabaya after traveling about 600 km from the Sewu mountain ranges to the southest of Surakarta. The Solo River is divided into three basins, which are the Upper Solo River, the Madiun River and the Lower Solo River Basin. The project area of the lower Solo riverimprovement is located on the flood prone area along the downstrem reaches of the Solo river and its tributaries.
The government of Indonesia (GOI) recognized the importance of flood disaster prevention from the past floods especially by the flood disasters in 1966 and 1968. In 1966, the Solo river caused the severest flooding bringing an inundation area of 142,000 ha and affecting population of 670,000 in the whole basin. The Government strengthened their policy to promote comprehensive development of the Solo river basin consisting of flood control, watershed management, water resources development and their related works. For an executing agency for the overall basin development, the Solo River Project Office was established in 1969, and was recognized as an executing board for the whole the Solo River Basin Development Projects.
OTCA’s master Plan Study on the whole Solo river basin in 1974 formulated a comprehensive flood control plan as well as water resources development plan. GOI carried out the detailed desigd of the Lower Solo River Improvement Project by financial assistance of JBIC (OECF). Afterwards, JBIC (OECF) Loan agreement for Phase-I was made in 1995, and implementation was enforced in early 1996 and presently in progress towards completion in 2004.
OBJECTIVES OF THE PROJECT
The project aims at an overall integratedbasin development for both the function of flood control and water resources development in order to contribute to the stabilization of public welfare and to acceleration of agricultural activity and economic development in the national and regional aspects. The projects has two objectives, that is, the one as the objective is to mitigate flood damages on the flood prone areas along the Lower Solo river and the other objectives is to develop water resources for water supply to the downstream areas and the north coastal area.
LOWER SOLO RIVER IMPROVEMENT PROJECT, PHASE-I
PROJECT FEATURES
A. Floodway
1. Floodway Channel
a. Length : 12.50 m
b. Bottom width : 100 m
2. Jetty (on both bank) : 2,200 m
3. Dyke : 22.16 km
4. Parapet wall : 997 m
5. Inlet Gate
a. Gated weir total width : 43.5 m
b. Steel Slide gate : 3 nos
6. Siphon : 1 unit
7. Bridge
a. Newly constructed : 3 nos
b. Modification of existing bridge : 1 no.
c. Village bridge : 2 nos
8. Dropstructure : 2 nos
9. Rubber dam : 1 unit
10. Sluiceway
a. Drainage facilities : 13 nos
b. Irrigation facilitis : 9 nos
c. Drain Inlet : 9 nos
d. Cross drain : 2 nos
11. Inspection road : 18.4 km
B. River Improvement Works
1. Dyking : 89.7 km
a. Newly construction : 26.6 km
b. Heightening : 63.1 km
2. Short-cut channel
a. Length : 2.2 km
b. Bottom width : 120 m
3. Parapet wall : 12,663 m
4. Low water channel revetment : 3,075 m
5. High water channel revetment : 1,284 m
6. Sluiceway
a. Newly constructed : 29 nos
b. Extention : 26 nos
c. Modification : 3 nos
7. Drainage canal
a. Connection canal : 11 km
b. Cross drain : 22 nos
C. Babat Barrage
1. Babat barrage
a. Gated weir width : 137.5 m
b. Barrage check gate including
flap and hoist : 1 nos
c. Barrage check gate with hoist : 6 nos
d. Discharge control gate : 1 no.
e. Intake gate including hoist and
Trashrack : 1 no.
f. Stoplog for check and control gates : 9 unit
2. Road : 8 km
D. Jabung Inlet Structure
1. Village bridge : 1 no.
2. Road : 7.2 km
3. Low water channel revetment : 143 m
E. Jabung Outlet Structure
1. Jabung Outlet Gate
a. Gated weir total width : 17 m
b. Non gated weir total width : 50 m
c. Flood control gate : 2 nos
d. Discharge control gate : 1 no.
e. Intake gate for irrigation : 1 no.
2. Gelap canal
a. Length : 4,300 m
b. Bottom width : 39 m
PROJECT COST
The project implementation of Phase-I is financially assisted by the japan bank for International Cooperation (JBIC’s Loan No. IP-450) Japan. The loan is valid until August 28, 2004 and the amount of the loan proceeds is 10,796 million.
LOWER SOLO RIVER IMPROVEMENT PROJECT, PHASE-I
FLOOD CONTROL IN DOWNSTREAM AREA FROM BABAT
Flood control in down stream area from Babat town is made by the combination of Jabung retarding basin, Floodway and Dyking. In the Phase-I, Floodway and levee along the Solo river is completed. But the construction of the Jabung retarding basin is still remained.
Short term plan of flood control is applied 1,180 ha for Jabung retarding basin and long term plan is by expanded 5,100 ha.
WATER RESOURCES DEVELOPMENT
Water supply in surrounding Lower Solo river basin is studied in Phase-I. And Babat barrage is selected to construct in Phasr-I. Babat barrage can supply irrigation water to Jero swamp area (14,952 ha), left bank area (3,160 ha) of Lower Solo river through the Leideng Gelap canal. Domestic and industrial water also can be suplied to Kab. Lamongan (1.425 m3/s), northen and central area of Kab. Gresik (3.081 m3/s) and Tuban city area (2.612 m3/s). However, additional structures are necessary ti satisfy water supply scheme in Phase-II.
BABAT BARRAGE
Objectives of Babat Barrage
Habitants in the Lower Solo river basin often suffers a lack of water in dry season. The Babat barrage is one component of Long Channel Storage which is considered to water resources development in Lower Solo river basin.
Function of Babat Barrage are as follows:
a. Irrigation water supply to Jero Swamp area through intake, headrace and primary canal
b. Irrigation water supply to left bank of Lower Solo river through Jabung retarding basin
c. Domestic and industrial water supply to Kab. Tuban
d. Domestic and industrial water supply to Kab. lamongan
e. Domestic and industrial water supply to northen and central area of Kab. Gresik through Sembayat barrage.
Feature of Babat Barrage
1. Hydraulic Condition :
a. Flood discharge : 3,170 m3/sec
b. Flood water level : EL. 8.40 m
c. Full supply water level : EL. 5.70 m
d. Max. supply water discharge : 20 m3/sec
e. Tail water level
- Highest high tide level : EL. - 0.45 m
- Mean tide level : EL. - 1.29 m
- Lowest low tide level : EL. - 2.13 m
2. Basic Structural Dimensions:
1) Civil Structure
Barrage Type : Gated weir
Gate Sill Elevation : EL. – 1.30 m
Aron Elevation : EL. – 3.30 m to EL. – 3.60 m
Barrage Width : 137.50 m
Barrage Legth : 70.00 m
Foundation Type : Pile Foundation
2) Gates
Flood Gate
- Gate Type : Radial gate (one gate with flap gate)
- Clear span of gate : 15.00 m per gate
- Gate height : 7.10 m
- Gate number : 7 nos
Discharge Control Gate
- Gate type : Radial type (with flap gate)
- Clear span : 7.50 m
- Gate height : 9.00 m
- Gate number : 1 no.
Bypass Gate
- Gate type : Fixed wheel gate (4 edges rubber seal)
- Clear span : 2.05 m
- Gate height : 2.50 m
- Gate number : 2 nos
Construction Cost Rp. 162 billion (Budget Source : APBN and JBIC loan)
Contractor Civil Work PT. ADHI KARYA
Hydromechanical Work MES-WIKA JO.
NECESSITY OF PHASE-II
Flood Control
Lower Solo river improvement was planned to construct the leeve between Cepu and river mouth. In the Phase-I, leeve construction is carried out between Babat and river mouth. At the present, it still remains between Cepu and Babat. Even the Phase-I is completed, inundation is occurred downstream of Babat because flood water overflows from upstream of Babat. And upstream area of Lower Solo river is sometimes inundated by small scale flood. Therefore, levee construction should be carried out between Cepu and Babat.
Water Use
In the dry season, a lack of water is very serious problem in/surrounding Lower Solo river basin. Habitants in this area are looking forward to use adequate waterin the dry season. It is necesaary to construct storage structures. The Long Channel Storage was studied to minimize resettlement and land compensation in the Comprehensive Development and Management Plan. The Long Channel Storage consist of the Sembayat barrage, the Babat barrage (completion in Phase-I), the Bojonegoro barrage and the Karangnongko dam.
LOWER SOLO RIVER IMPROVEMENT PROJECT, PHASE-II
Project Component Phase-II
(1) River Improvement Works of the Lower Solo river between Babat and Cepu town, (Packages II-1~ II-6: right bank, Packages III-1 ~ III-5: left bank), as well as remaining works in Phase-I.
(2) Construction of Ring dam and Drainage System for Jabung retarding basin (Packages J-2(1)).
(3) Construction of Bojonegoro barrage (Package BJ)
(4) Jero Swamp Improvement (Package JS(1))
(5) Construction of Sembayat barrage (Packages Sb(1))
(6) Construction of Karangnongko dam (Package K(1))
(7) Installation of Flood Forecasting and Warning System (Package FFWS)
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