Problems associated with implementation of bioengineering in hill road construction in Nepal

Abstract

The landslide disaster, feeble geology, rapid deforestation, poor drainage system, and increase in mechanical strain have weakened the Krishna Bhir slope, Prithvi Highway, Dhading, Nepal. The objective of this article was to study about the problems associated with bioengineering implementation in hill road construction with the future recommendations. For primary research, map study, field observation, in-depth interview, focus-group discussion, and questionnaire survey were used as an instrument for the field study. Published reports, papers, thesis, database and manuals, and field observation were also reviewed. Landslide caused the loss of property, ill effects on lifestyle, disturbance in movement of goods and services, loss of availability of water due to damage in water supply system, damage in sewage disposal system, etc. During the construction period using bioengineering technique, major problem occurred during installation of the bioengineered system (RII = 0.791), lack of training during construction (RII = 0.839), unavailability of space (RII = 0.817), inadequate supply of appropriate instruments (RII = 0.821), and improper selection of vegetation types (RII = 0.839). The major problems were also seen during site monitoring and evaluation (RII = 0.853). Proper selection of plant species (RII = 0.936) before implementation of bioengineering technique is needed at hill road, but the high installation costs (RII = 0.841) could be the major limitation. Bioengineering application has a bright future if proper actions are taken in time. Solutions need to be formulated and implemented by understanding the major limitations of bioengineering technique.

Introduction

Bioengineering is an alternative for the usual engineering techniques where vegetation is used as a primary tool. It uses green infrastructure to protect from natural calamities like landslide and soil erosion in the form of soil stabilization and improved drainage function [1]. The civil engineering has been incorporating the concept of bioengineering in order to reduce the overall cost of the mitigation measures used for landslide. The immediate protection in the form of physical structure is provided by physical construction techniques, whereas vegetation techniques used in bioengineering need time to show its effect [2]. The Nepalese geology has also been very favorable to bioengineering techniques in the recent times due to its cost-effectiveness, low labor cost, and local availability of useful materials [3].

Nepal is a mountainous country consisting of three major regions, namely mountains, hills, and Terai. Most hill districts of Nepal lack of adequate rural transportation resulting in isolation, poor access to markets, high prices of commodities, irregular public services, and low economic opportunities [4]. To address the above said social inequalities and physical, social, and economic hardship to the local people due to lack of access, the government of Nepal has given high priority to construct hill roads as a prime infrastructure services to assist in realizing the goal of alleviation of poverty. The construction of road in these regions has become a major challenge which has introduced the concept of Green Road and bioengineering technique for solving these problems [5]. The concept of bioengineering in hill road construction was introduced in Nepal 40 years ago with roadside plantations in a US-assisted project on the Dhangadhi-Dadeldhura highway in western Nepal [6]. Nepal has been suffering from water-induced disaster problems including soil erosion, debris flow, landslides, and flooding which are common due to the unstable landscape. Soil erosion is the most important driving force for the degradation of upland and mountain ecosystems. The main soil bioengineering techniques used in Nepal are brush layering, palisades, live check dams, fascines, and vegetative stone pitching [7].

The Krishna Bhir is a cliff located in Dhading District by the side of Prithivi Highway, approximately 83 km from Kathmandu Valley. The landslide disaster at Krishna Bhir has become very infamous due to its serious and dreadful effects which have worsened the socio-economic and environmental condition of the region [8]. The feeble geology, rapid deforestation, poor drainage system, and increase in mechanical activities have further weakened the Krishna Bhir slope leading to frequent landslides. Bioengineering was applied to this area by the Department of Road — Nepal, in order to stop the mass movement of the hill slope and to strengthen it. Although it was an effective solution, the Krishna Bhir slope has reverted back to its volatile state again [9]. Hence, this article evaluates the problems of hill road construction at Krishna Bhir using bioengineering techniques with the future recommendations to prevent the impending landslide problems.

Methods

This study utilizes both the primary and secondary research. A mixed-method research is used in the study where combination of both the qualitative and quantitative data is used in order to answer the designated research question. Primary data was collected through semi-structured questionnaire, focus-group discussion, in-depth interviews (IDI) with key informats, and direct field observation. Secondary data regarding the research was collected from published and unpublished literature of department of roads, detailed project report (DPR) of Krishnabhir, and different publications of the Department of Road (DoR) books, newspapers, journal, and research papers and from different related concerned offices.

The study area for the study covered two selective sites which include Krishnabhir (Jogimara) and Banepa Bardibas Highway. A total of 240 respondents were selected for the survey which included 180 technical respondents (engineers and subengineers) and 60 non-technical respondents (community people, traffic police). For quantitative data, a set of multiple-choice questionnaires was prepared for all the respondents where Likert’s scale was used to get views of each respondent with the scale ranging from 1 to 5 (1 = no impacts, 2 = negligible impact, 3 = marginal impact, 4 = moderate impact, and 5 = major impact). Relative importance index (RII) was used to summarize the impact of each problem indicator [10].

$$RII=\mathrm({\Sigma W}/N)\times A$$

where

W = Weighting as assigned on Likert’s scale by each respondent in a range from 1 to 5 (1 = no impacts, 2 = negligible impact, 3 = marginal impact, 4 = moderate impact, and 5 = major impact)

A = Highest weight (here, it is 5)

N = Total number in the sample

For the qualitative data, field observation was carried out by personal visitation of the construction sites and collection of information. MAP surveys are derived from traditional private sector distribution surveys using lot quality assurance sampling (LQAS) [11]. The IDI was carried out among the six experts who were highly experienced and qualified on the field of road maintenance and construction works. Semi-structured interview questionnaires were prepared for the respondents, and the response was recorded in the form of video as well as written text. Focus-group discussions were carried out between road construction experts, road users, road supervisors, and construction contractors. The qualitative data was analyzed using descriptive statistics and presented in the graphical form of charts, figures, and tables. Computer software, ArcGIS, and Microsoft Tools were used for the overall data analysis. Privacy, confidentiality, and anonymity were maintained throughout the research, and written consent was taken from all the selected participants.

Results

Socio-demographic data

The general sociodemographic information of the respondents revealed that most of them are from age group of 40–49 (technical, 53%) and 18–29 (non-technical, 48%). Most of the technical as well as nontechnical respondents were males (79% and 73%, respectively). Most of the technical respondents were engineers (54%), employed (57%), had experience of more than 5 years (65%), and were involved in nongovernmental jobs (66%). The nontechnical respondents were mostly farmers (34%) and local representatives (33%).

Problems due to landslide

According to the survey conducted among 240 respondents, Fig. 1 shows that area hit by landslide that had fragile rocks mostly suffered problems of roads being washed away, road blockage, traffic problems, damage to drainage system, loss of trees, loss of property, and increase of accidents. Most of the respondents agreed that all the above were the major problems in the landslide hit area. In addition, most of the respondents agreed that there was loss of property and lifestyle (79%), disturbance in maintenance of goods and services (57%), loss of water availability, quality and quantity (79%), damage to water supply system (60%), and damage to sewage disposal system (58%) due to landslide (Table 1).

Fig. 1

Major problems after landslide

Table 1 Perception on problems after landslide

Problems before construction period

Table 2 shows that among 180 respondents, majority of them agreed that the improper planning at office before construction, inadequate priorities of office work before project execution, improper division of site segment, problems with access to site, lack of determining civil engineering works, improper selection of bioengineering technique, improper design of the civil engineering structure and bioengineering system, improper calculations of required quantities and rates, problems in budget finalization, and improper preparation of documents for the project were major hurdles before the implementation of the construction work. The inadequate priorities of office work before project execution (RII = 0/954, mean = 4.772) were the major problem before construction work started using the bioengineering techniques.

Table 2 Problems before construction work (n = 180)

Problems during construction period

According to Table 3, the improper installation of bioengineered system (RII = 0.791, mean = 3.956) was the main problem during the construction period using the bioengineering technique. In terms of the involvement of local community during construction, lack of training (RII = 0.839, mean = 4.194) was the major hurdle that caused the lack of involvement. In terms of transportation of the construction material, damaged road conditions (RII = 0.777, mean = 3.883) were also another major hurdle that created problems construction. The unavailability of space (RII = 0.817, mean = 4.083) during the storage of construction material created another major problems during the construction works. There were no major disasters during the construction according to the respondents. The inappropriate supply of construction materials (RII = 0.821, mean = 4.106) caused major problems in mobilization of the constructions equipments during the construction phase. In terms of mobilization of manpower, lack for training for the workers before and during the construction period (R = 0.839, mean = 4.194) posed a major construction problem.

Table 3 Problems during construction work (n = 180)

The improper selection of the vegetation types (R = 0.839, mean = 4.194) during the construction phase also caused problems in proper utilization of the available plant species. Bioengineering is only successful if there is availability of proper seedbed, but there was unavailability of seedbed preparation at the site due to lack of seedbed fertilization (R = 0.829, mean = 4.144). Political issues also caused problems during construction when demand of the job to the political workers increased (R = 0.891, mean = 4.456) at the construction site (Table 3).

Benefits after bioengineering

Among the 180 technical respondents, majority agreed that after the implementation of bioengineering construction works, the maintenance costs of the live plants around that area decreased after their establishment (RII = 0.972, mean = 4.861). Other changes that were seen include slope stabilization, erosion control, low cost and long-term maintenance cost than traditional methods, ground water control, and environmental benefits of wild life habitat (Table 4).

Table 4 Benefits after bioengineering (n = 180)

Problems after construction work

According to the respondents, the major problem after the implementation of the bioengineering during construction work was seen in site monitoring and evaluation (RII = 0.853, mean = 4.267) (Table 5). The problems during the maintenance work was seen mainly in the mulching process (RII = 0.184, mean = 4.072). During the maintenance, the workers were mostly using the improper method of mulching as well as weeding at the planted sites (Table 6).

Table 5 Problems after construction work (n = 180)

Table 6 Problems during site monitoring and evaluation (n = 180)

Purposed solutions of problems before implementation

Among the 180 technical respondents, most of them agreed to the fact that the proper selection of plant and species (RII = 0.936, mean = 4.678) could be one of major solutions to avoid the problems (Table 7). Other solutions include focus on appropriate design and technology, consideration to plant propagation, proper mobilization of construction equipments and tools, and training for the manpower.

Table 7 Purposed solutions of the problems (n = 180)

Limitations of the bioengineering technique

In terms of the major limitations of the bioengineering technique (Table 8), the high construction and installation cost (RII = 0.841, mean = 4.2056) and limited amount of locally adapted plants around that area (RII = 0.814, mean = 4.072) were the most relevant limitations. Other limitations include the following: takes long term for functioning, construction and installation cost are high, and difficulty to control human or animal traffic at the site.

Table 8 Limitations of bioengineering technique (n = 180)

Discussion

Bioengineering has been utilized in construction management for a very long time and is showing high relevance in the recent times. Live vegetation has been in use for a very time in order to reduce soil erosion, for bed stabilization, to protect seawalls and sand dunes from the force of water. Bioengineering provides long-term protection, which is capable of self-regeneration as well [12]. The increasing popularity of soil and water bioengineering constructions has paved way for living plants and supplementary materials to be included in various construction projects. It has also improved the ecological values and the values of landscape aesthetics together with the technical benefits of the bioengineering technique [13]. Soil bioengineering is present in Nepal since 30 years to deal with the problems of erosion on slopes, high way construction, and stabilization of the riverbank. Nepal’s landscape has been quite familiar to the bioengineering techniques as well, and many construction activities have started using the different bioengineering techniques. In terms of the projects in Nepal, the major bioengineering technique used is brush layering, palisades, live check dams, fascines, and vegetative stone pitching [3].

The above study was also conducted to evaluate the effectiveness of bioengineering techniques and the problems encountered while incorporating the bioengineering technique in the construction works at Krishna Bhir and Banepa Bardibas Highway. Both the responses of the technical personnel and the nontechnical personnel in the study area were collected to know about the current situation of the construction site, implementation of bioengineering technique, its usefulness in the construction area, and its after effect. From the responses obtained, it was concluded that although the bioengineering technique had been beneficial to solve the problems related to landslide and soil erosion, the lack of preparation, design, proper implementation, maintenance, monitoring, evaluation, and other relevant factors had caused the slope and road to revert-back to its deteriorating state. According to [14], the poor preparation and maintenance culture are the major problems that affect the projects like the one in this research. The problems in proper implementation of the bioengineering technique, problems in transportation of raw materials, problems in storage of raw materials, lack of community participation, political issues, lack of mobilization of manpower, lack of proper selection of plant species for bioengineering, and lack of seedbed for fertilization caused ruckus during the construction activities. In addition, political influences during the construction phase also caused problems here and there. Projects in Nepal have a high political influence and changes its picture according to the people in power which was also seen in this project [15]. Not only during the construction period the improper planning and design of the project before its implementation were responsible but also for the future events that occurred in the area. Problems like improper planning at office before construction, inadequate priorities of office work before project execution, improper division of site segment, problems with access to site, lack of determining civil engineering works, improper selection of bioengineering technique, improper design of the civil engineering structure and bioengineering system, improper calculations of required quantities and rates, problems in budget finalization, and improper preparation of documents for the project were some of the hurdles that created a negative impact on the project even before it started. After the construction was over, the lack of proper maintenance activities, monitoring, and evaluation added up to already existing problems. After the evaluation of all the results, it can be clearly seen that the problems occurred due to the unfamiliarity, lack of awareness, lack of knowledge, lack of training, and lack of skills among the people that were fully involved in the construction work using the bioengineering technique. Due to lack of proper information and knowledge about the bioengineering technique, the pre and post phase of the construction work suffered a lot. Lack of awareness among the community people also added up to the problems. The participation of users in up-front decision-making (within the project design and planning phases, including the capacity to make meaningful choices among a series of options offered to them) leads to positive results in terms of any kind of construction project which was lacking in this project [16]. People responsible for carrying out the construction design, choosing the bioengineering tools and system, budget finalization, and preparation of initial documents, and fixing out priorities seemed to lacking proper training and skills to perform their responsibility. The cracks in the initial phase caused the project to get affected in the later phase. Unfamiliarity about the seasonal plants, importance of seedbeds, vegetation type, and plant selection in construction bioengineering may caused more hurdles leading to an unsatisfactory result.

Although benefits like slope stabilization, erosion control, ground water control, protection of wild life habitat, improved water quality and quantity, promotion of aesthetic values, reduction of disaster, development of agricultural land, and improvement in the life span of road pavement were seen [17], these were not there to stay for a long term. The failure of post implementation maintenance phase created a big question mark on the effectiveness and long-term stability of the construction project. Problems in protection of planted sites, weeding, mulching, grass cutting, watering, and lack of preventive maintenance caused the implemented construction work to suffer for long term. So, the technical respondents emphasized that before starting any bioengineering construction works in the future, special emphasis should be placed on appropriate design and technology, proper selection of plant and species, proper plant propagation, proper mobilization of construction equipment and tools, proper training of manpower, proper awareness of bioengineering principles to the local community, proper monitoring and supervisions, and proper awareness about limit, rules, and regulations relating to the bioengineering technique. With the emphasis on these factors, the projects like these could lead to a more successful result for a long term. But we should not forget that every process and procedure has its own limitations. Bioengineering also has its own limitations which need to be considered in the initial phases, so as to receive least problems in the execution of any projects in the future [18]. Lack of skilled bioengineering experts, expensive construction and installations costs, unpredictability of plants, and unfamiliar installation techniques are the major limitations of bioengineering according this study. Hence, in the future, the projects like the Krishna Bhir construction need to focus on initial phase preparation and post implementation maintenance together with limitations of the bioengineering implementation for the success and effectiveness of the project.

Conclusions

Hence, bioengineering can be a very successful tool for any construction project like the one in Krishna Bhir and Banepa Bardibas Highway if the focus is shifted on making people aware of bioengineering and providing required training and knowledge to respective personnels. The initial design and preparation phase should be given special consideration, so that bioengineering techniques are executed efficiently. During the construction phases, manpower utilization, raw material availability, skill development, etc. need to be given special focus for proper execution of the project. Post implementation maintenance also need to go hand in hand with the project so that overall effective result is obtained. Although there were several problems during the hill road construction and post maintenance, bioengineering application has a bright future if proper actions are taken in time. Solutions need to be formulated and implemented by understanding the major limitations of bioengineering technique in the near future for the success of it in the hill road construction works.