2006 — Suggestions on Flood Control Embankment Construction for the Lishui River Scenic Belt (Part 2)
2. Design concept. The already-built embankment section, on the whole, is of a single flood-control type, and its renovation is imperative. Since this article focuses on the embankment yet to be built, the renovation of the existing section is omitted. The design of the embankment to be built will all be carried out on un-channelized riverbanks. This allows us to conduct individualized design based on different terrains and riverbank alignments
This article has been compiled from historical materials in the "Zhangjiajie Tour Guide Network" (33519.com · City Overview section). Some administrative divisions, population, socioeconomic data, and policy information may be outdated and are for reference only; for the latest situation, please refer to official releases by the local government and scenic areas.
II. Design Concept.
The already-built flood control embankment section, taken as a whole, belongs to the single-purpose flood control type, and its renovation is an imperative matter. Since the focus of this article is on the embankment sections yet to be built, how to renovate the already-built sections is omitted here.
The design of the flood control embankments yet to be built will all be carried out on riverbanks that have not been channelized. This provides considerable space for us to carry out individualized design according to different terrains and landforms and the alignment of the river and embankments, and to proceed from reality in using earthen embankment techniques to replace cement embankments.
(1) North Bank Embankment of the Lishui Scenic Belt (from upstream to downstream).
From Mulongtan Dam to the north end of Mulongtan Bridge: rockfill methods may be used for bank protection.
Dayongqiao Park: This park takes greening as its main content and leisure as its main function, so the embankment within the park must likewise embody greening characteristics, and moreover must embody the natural and wild features of flood control engineering, planting native species to form a boundary place where people can be close to the water for viewing and stopping to rest.
From the left end of Zhangjiajie International Hotel to the left side of the north end of Lishui Bridge (extending to where the Shoujin Rock section meets the existing flood control embankment): The riverside sections in this area are all natural rock and rock strata, and whether in relative height or absolute height, they are much higher than the already-built flood control embankment. No flood in history has ever risen above the embankment of this section, so the riverside interface of this section basically needs no bank protection; it is only necessary to maintain and preserve its natural ecology. Where bank protection is truly needed in local sections, materials such as stone or wood should be used.
The area around Lusiwang Ferry (from Baotagang to the north end of Lusiwang Bridge): This area (including the opposite bank) has fairly obvious features of shoals, wetlands, and near-shore reed beds and shrub thickets, and thus many egrets roost here, earning it the reputation of "the place where egrets dance." On this basis, an Egret Paradise can be built. After the Hongbiyan Dam is completed and impounds water, there should still be mudflats and wetlands here, with designed native aquatic and wetland plants arranged in a well-spaced and picturesque manner, convenient for birds such as egrets and wild ducks to roost freely, and also convenient for people to enter and exit freely.
From the left side of the north end of Lusiwang Bridge to Hongbiyan Dam: The riverbank of this section is mainly hillside (with a township-level road passing through the hillside). This kind of water-land interlaced zone is precisely the living and migration area for terrestrial and aquatic flora and fauna. Therefore, the design of the bank slope protection works should combine with the undulating and changeable terrain to form a design with multiple elevations and multiple cross-sections that is both embankment and hill, using rockfill with good reverse-filter and cushion-layer structures, porous concrete components, and flexible structures made of natural materials, avoiding as much as possible the use of hard, impermeable materials such as concrete. This will not only benefit the growth of plants, fish, and amphibians, but also make the embankment's appearance embody natural and wild characteristics.
(2) South Bank Embankment of the Lishui Scenic Belt (from upstream to downstream).
From Mulongtan Dam to the south end of Lishui Bridge (Note: The two sides of the south end of Mulongtan Bridge, reaching up to Mulongtan Dam and down to the right end of Juziyuan, are planned by the city as park construction): The entire line of bank protection is designed as gentle-slope earthen embankments, carefully laid out, with ornamental native trees (such as restoring the fire willow grove), shrubs, vines, and herbaceous plants planted in a well-spaced manner, forming an interface where people can be close to the river water. Some seating and platform plazas may be set up in between, making this an extension and expansion of the parks on both sides of the south end of Mulongtan Bridge—or rather, this entire area is a riverside park suitable for leisure.
Right side of the Ganxi River confluence: This place is currently a waste soil dumping ground. It is suggested that the municipal government immediately take measures and notify the relevant departments to stop waste soil dumping—using the currently piled earth slope as the foundation of an earthen embankment, opening it into a gentle-slope bank protection, and planting trees and grass together to stabilize the embankment and form a space full of wild charm; the bank land adjacent to the river water should be dug down to the same elevation as the riverbed bottom. Once the Hongbiyan Dam impounds water, this place will be a lake with green waves rippling! According to information provided by relevant persons, from Nanmenkou to Ganxikou, the world's longest covered bridge in Xiangxi style will be built. Then, one can imagine that this place will surely be a major highlight and point of excitement in the Lishui Scenic Belt.
The Guanliping section on the east and west sides of the south end of Guanyin Bridge: Taking into consideration the correspondence with the already-built flood control embankment in the old urban area on the opposite bank, this section adopts a sloped stone-masonry bank protection, with the upper part of the slope using porous concrete components for planting grass; the lower part of the slope laid with cobblestones; the embankment toe piled with stones; and the embankment top road surface designed accordingly based on the overall plan of the Lishui Scenic Belt.
Around Lusiwan Ferry: together with the ferry area on the opposite bank, it forms Bailu Lekuo. Therefore omitted.
From the southern end of the Lusiwang Bridge to the southern end of the Hongbiyan Dam: the riverbank here winds in a graceful, varied way, and a natural water-willow grove still survives. River bends, shallows, wetlands, grassy slopes, thickets, and reed beds are all distinctly present, and the natural ecology is in good condition. The design for this stretch of riverbank should mainly use earth-built embankments, combining with the changes in terrain to create a design that is both embankment and mound; native species should be planted in a timely manner, serving the dual purpose of reinforcing the embankment and enhancing its appearance; the riverbed should be treated to create deep channels and shallows, so as to benefit the growth of aquatic animals; and other corresponding measures should be adopted to genuinely give it the three functions of flood control, ecology, and landscape. This area can absolutely be built into a leisure and recreation site featuring the water-willow grove as its main characteristic.