Huludao-Xingcheng Coastal Trail

Challenge

The local climate and the site’s coastal cliffs presented multiple challenges to the siting and construction of the trail. First, because the tides push hundreds of tons of sea ice onto the shoreline during the cold winters, placement of the trail at lower elevations would require significant structural engineering and substantially increase overall construction costs. Second, rockfall from the natural weathering of the coastal cliffs would pose a safety threat if the trail were built at the bottom of the cliffs. Third, the design goal of preserving a large existing black pine forest patch with significant ecological value called for minimum disturbance from the trail construction. Fourth, safe crossings for the trail needed to be provided across 6 large gullies while preserving their hydrological and ecological functions.

Solution

The majority of the trail was built above the cliffs to avoid the significant cost of building on the ice-prone shoreline and the risks associated with rockfall. A majority of the trail design occurred on-site to determine the best route to prioritize the protection of the pine forest. In locations where it was impossible for the trail to bypass the forest, it was routed through areas with low tree density using low-impact construction methods that did not require the use of heavy equipment, such as raised boardwalks and pea gravel concrete paving. To traverse the gullies, the trail went inland to avoid the widest one (over 230 ft wide), and various cable or pillar wooden bridges were constructed to cross the other 5 gullies (30 to 230 ft wide). One bridge was built in a zigzag form to protect existing trees within the gully while adding more interest for trail hikers.

• The 3.7-mile-long trail connects 7 beaches, 11 major scenic spots, and 4 cultural and historical sites along the Bohai Sea coast, providing increased access to recreational opportunities and protecting the coastal ecosystem by reducing tourism pressure on the 2 most popular beaches.
• 8 staircases provide safe access to the 7 beaches, significantly reducing erosion potential for the cliffs. They replaced 5 existing improvised staircases, which were unsafe. 
• 3 wooden arch bridges extend across 3 gullies narrower than 30 ft. 5 rope or cable suspension bridges cross 5 gullies between 30 and 230 ft wide. 1 zigzag-style wooden bridge traverses an area with a large number of mature trees and creates an engaging experience along the trail for visitors.
• 15 viewing platforms provide superior views toward carefully-selected focal points such as the Camel Mountain peak and Juehua Island in the distance.
• 5 service areas, including restrooms, service stations, convenience stores, and parking lots, are located every 0.3 to 0.6 miles and total 0.75 acres in area.
• A mix of wind-resistant indigenous trees, shrubs, and groundcover vegetation were planted on bare earth to stabilize soil and slopes. This newly-planted area is approximately 12.4 acres and includes almost 3,000 newly-planted trees. Primary species include Chinese pine (Pinus tabulaeformis var. mukdensis), Chinese willow (Salix matsudana cv. Umbraculifera), tree-of-heaven (Ailanthus altissima), Japanese pagoda tree (Styphnolobium japonicum), and Chinese ash (Fraxinus chinensis).
• 2 stormwater infiltration areas along the trail incorporate pebbles from nearby beaches to manage runoff from the trail and minimize erosion from water flow down the hillside.
• Existing black pine trees within the 60- to 70-year-old native stand that could not be avoided by the designated route of the pathway were protected using pea gravel concrete paving, a semi-permeable paving system made of rounded 1/8-in to 3/8-in aggregates with little soil compaction underneath to give the tree roots access to growing space, water, and air. 
• Steep slopes within the gullies were stabilized with locally-sourced gravel. The platforms and rest areas were paved with local stones and slate from a nearby quarry in order to reflect the site’s natural characteristics.
• A solar lighting system consisting of 800 ground lights and 140 post lights provides 100% of the trail’s light.  

One of the major design goals was to express nature’s shan-shui (mountain-water) beauty and provide a cultural landscape appreciation experience. The term shan-shui describes traditional Chinese paintings that depict scenery–typically mountains and rivers–and in landscape design represents a balanced approach that does not seek to dominate a landscape’s natural scenery. To achieve a shan-shui aesthetic, critical natural and cultural resources were first identified through site investigations. Those with superior natural beauty, including Turtle Mountain, Eagle Mouth Mountain, the black pine forest, the flower valley, and the rock shoal, were strictly preserved as targets for scenic views. Those with cultural significance, such as the Dragon Look Back Plaza and Mazu Temple, were highlighted as viewing platforms or walking destinations. Exceptional places for viewing the mountain peaks, islands, and ocean in the distance were then identified and later became locations for viewing platforms and pagodas. All sight lines were carefully designed to achieve a harmonious relationship between the trail, the carefully-scaled structures, and their surrounding scenic landscape.

One of the major challenges in routing the trail was the cold climate and ice-prone shoreline. The trail rises and falls in topography between the shoreline and cliff. If the trail were to be built entirely on the shoreline, the construction would have cost $17.7 million due to the structural engineering required to withstand the hundreds of tons of sea ice that are pushed to the shore annually. This is over 3 times the cost of the trail as it was built. 

• Regional-scale recreational trail projects need to be coordinated with regional transportation planning in the early stages to reduce overall environmental impacts. The June 2017 intercept survey revealed that 37.5% of the 64 respondents drive to the trail due to the significant distance (5.5–7 miles) from the trail to central Huludao or Xingcheng. 17% of private car users visit the trail more than 3 times per week. Although a public transportation system with 2 bus lines is already in place, increasing bus frequency during peak times could potentially reduce the number of car trips.
• Since the trail’s completion in August 2012, the section that traverses the existing native black pine stand, which is paved with pea gravel concrete, has effectively protected the trees located in the middle of the trail. No cracks were found in the paving during a 2017 site investigation, and every tree had survived over the 5 years.
• A gap in current park design codes at the national level was discovered: the slope standards for parks were not applicable to sites with significant terrain changes. To provide access from the Coastal Trail to the beaches, staircases needed to be built on cliffs with 40 to 60% slopes, overcoming 40 to 80 ft in elevation difference between the cliff and the shoreline. After some research on China’s mountainous regions, designers elected to design the slopes of the trail to conform to standards developed in the City of Chongqing. Chongqing was selected as a precedent because it is the largest mountainous metropolis in China, with an average slope of 14% and maximum slope of 180% in its downtown area.
• It is common for remote sites such as this to lack preexisting site survey data sufficient to support design and construction. The distant location of the landscape architect’s office in Beijing made it even more challenging to complete the design phase within only 13 months as required by the client. As a result, conducting on-site design and construction supervision proved to be the most cost-effective way to ensure design accuracy and achieve desired landscape outcomes.

Ashlar: Xingcheng Kaolin
Antiseptic Wood: Manchuria
Concrete: Huludao Yu Zhi Concrete Batching Plant
Rebar: Ling Yuan Iron and Steel Co. Ltd., Lingyuan, Liaoning, China

Project Team

Executive Architect, Landscape Architect: Research Center for Landscape Architecture Planning at Beijing Tsinghua Tongheng Urban Planning & Design Institute (THUPDI)
Civil Engineer: Shenyang Municipal Engineering Design & Research Institute
General Contractor: China Construction Second Engineering Bureau Ltd.
Investor and Project Owner: Huludao Longwan District Management Committee

Role of the Landscape Architect

The landscape architects led a team of ecologists, recreation planners, and civil engineers in developing the plan and design. They also administered construction and cooperated with contractors for on-site design to better deal with the complex terrain and diverse vegetation cover and carefully control landscape effect.