Task 1.6. Accomplished technical survey of the technical status of the existing river dikes and inland dike around the wetland area Belene island. Technical report for the purpose of the design
1. Inspection for the conditions of dikes is accomplished. Places with disintegrates of the covering or some other notes mentioned in the report are coordinated and will be mentioned in the map materials attached to the report.
The inspections for the Danube river dike and inland dike for Belene are prepared from:
Eng. Ilian Dimov Iliev – hydro-meliorative building, head of department “Irrigation systems” Ltd Rousse.
2. The detailed survey of the crowns of the dikes is accomplished through coordination and survey according to the length of points on the crowns of dikes through 100 m or on typical places. This is preconditioning for comparison these data to the designed ones (where there are such kind of data).
The surveys are prepared in the following periods:
For Belene: 22-26 April 2003
Team:Eng. Ilko Georgiev
Eng. Radoslav Pavlov
Supporting staff – 3 persons
Longitudinal sections of the dikes are prepared in scales: H 1:2500 and V 1:250 as a result from the surveys:
of the Danube River dike in the part bordering (to the north, east and south) the zone and of the north-south direction dike bordering the zone to the west.
Two sections are formed: 1 – Danube River dike, 5 drawings for each one of them; 2 – inland dike, 2 drawings for each one of them.
Attachment:
Longitudinal section, Belene, Scale ML 1:2500Scale, MH 1:250
3. Comparison of the data from the real survey with the designed levels
Only data for the Danube River dike for the area of Brushlen-Kalimok zone are found from the sources of “Irrigation systems”.
4. Report for the inspection and the surveys of:
According to the confirmed terms of references during the inspection are accomplished the following tasks:
І. INSPECTION OF THE CONDITION OF THE DIKES
Danube River dikes protecting the Belene wetland are located in Belene Island. The dikes are three: North Danube dike – it is located between the Danube river and the north border of the wetland; South Danube dike – it is located between the Danube river and the south border of the wetland and Second Danube dike – it parcels out the Island into two parts – east and west ones. The total length of the dikes is 21,514 km. Ministry of justice supports the dikes.
The cross section of the dike is trapezium-shaped with the following basic measurements:
Width of the crown – 4 m
Average height of the dike 4,50-5,00 m
Width of the basis of the dike – 20,00-22,00 m
Slope of the dike – average 1:1,5
1. Inspection the condition of North and South protected dikes
The total length of the dikes is 16.129 km. The water and land dike slope are in good condition. There are low bushes and single trees at some places. There are not any sectors or local places with filtration founded during the inspection. There are not any landslides at the foot or the crown of the dikes founded during the inspection. The dike does not need heaping as was seen from the attached longitudinal sections. It is required the crown covering of the dike to be improved in order to be passable during the whole year. It is required in the sectors of inlet-outlet facilities to be constructed places for turns off of vehicles.
There are not data for designed levels and implemented levels and for this reason comparison of the dike subsides cannot be done.
2. Inspection the condition of Second sector dike
The length of the dike is 5384,87 m. It parcels out the Island into two parts – east and west ones.
According a design the dike is built at level approximately 22-22,5 m and there are subsides and collapses below this level only in some areas. The sectors in the following table have to be heaped and leveled in order to improve the dike passable.
Table 1
| km |
length |
Levels for writing out | ||
| From km |
To km |
m |
from |
to |
| 1+722 |
1+734 |
12 |
21,40 |
22,20 |
| 2+006 |
2+085 |
79 |
21,50 |
22,20 |
| 3+995 |
4+025 |
30 |
19,00 |
22,00 |
| 5+295 |
5+385 |
90 |
23,50 |
25,00 |
As a result of passing of agricultural and other machinery wheel-tracks are formed on the crown of the dike and during bad weather dike is impassable. It is necessary to be constructed solid road surface along the length of the dike to ensure all year access to the inlet/outlet facility in the north end of the Second section dike and to the observation places in the north side of Wetland
A drainpipe exists at km 4+007 through which water passes from the west side of the island to the east side and through an exist sewerage it leads to the drainage pumping station. In the construction of Wetland this drain-pipe should be closed and in the future drain water get across the dike by pumps.
Level crown in the end of middle dike is lower with about 1.5 – 2 m than level crust of south protecting dike and passing up/down is difficult. It is necessary the section from km 5+295 to km 5+385 to be heaped with purpose of ensuring easy passage from one to another dike.
Table 2
| km |
length |
Level dike crown | ||
| In the moment |
After heaping | |||
| 5+295 |
5+385 |
90 |
23,50 |
25,00 |
West side of the dike in the sections indicated in Table 3 level terrain in dike foot is under designed flood level (level 20). It is necessary for these sections to be done fortifications of dike slope to be protected from possible landslide.
Табл.3| Km |
Length |
Levels terrain in dike foot | |||||
| From km |
To km |
m |
from |
to | |||
| 0+720 |
0+905 |
185 |
19,85 |
19,95 | |||
| 1+245 |
1+315,72 |
70 |
19,80 |
||||
| 3+205 |
3+340 |
135 |
19,98 |
19,55 | |||
| 4+007 |
19,00 |
||||||
| 4+103 |
4+158 |
55 |
19,77 |
19,80 | |||
| 4+211 |
4+781 |
670 |
19,40 |
19,80 | |||
3. Condition of the drainage channel nearby Second sector dike
At the present nearby Second sector dike there are constructed drainage channels in the sections of Block VІІ – in the north side and in the section of Block ХV and ХVІ. In the middle of the channel a drainpipe is constructed for getting across drain water to the east side of the island. Along the dike there are no drainage facilities in the area of the farmyard.
During the inspection of drainage channel in the north side was ascertained that the section from 0+892 m to 1+245 m is overgrown with rush, small bushes and small single trees. The channel is possible to be used in the future. It is necessary to be done cleaning and dragging of the channel to execute its purpose in the future after Wetland construction.
Through drainage channel in the section of Block ХV and ХVІ at the present moment is ensured draining of areas used for agriculture production. In the future along the whole length of the section should be designed and constructed new channel for protecting west side of the island against the percolating under the Second sector dike Wetland water. Second function of the channel should to be used as a sewer for collecting and leading of drainage water from the whole west side of the island to the mobile pumping station.
Main recommendations for improvement functional condition and service use of the dikes are:
1. Cleaning of crown, slopes and rights of way of north and south protecting dikes from single trees and bushes
2. Erection of Second sector dike in the above-mentioned sections;
3. Construction of drainage channel along the whole length of Second sector dike
4. Improvement road ability of the dike crowns with a view to ensure maintenance and service use of inlet/outlet facilities an ensure conditions for surveillance
5. Widening of the crown of the north and south dikes at least at three places (in the middle of the straight sections and inlet/outlet facilities) with the purpose of assuring conditions for normal crossing and change traffic direction of service vehicles.
Attachments:
1. Sites of longitudinal sections Scale 1: 10 000
2. Longitudinal section Belene 7pcs
Scales 1: 2500 / 250