| Summary: | 博士 === 國立中興大學 === 水土保持學系所 === 100 === Dakeng area are known as City Garden of Taichung. In addition to the agricultural production, the government is trying hard tp promote the integration of leisure and tourism, agriculture and water resources for a new social area "Da-Sing life circle" to expand the scale of industry in both tourism and agriculture in recent years.
This study investigate the potential and problems of Da-keng area slope land in terms of on slope stability, distribution of water resources, tourism-oriented development and urban planning.
In study of the influence of geological factor on slope stability, the results show that 368 hectares-wide potential land slide zone area in Da-keng area PQc accounted for 21.3% of the potential land slide zone and P2 only 7.1%. This results also indicate that in potential analysis of regionalization of landslides in the past years, impact factor selected in analysis is significant for PQc geological formation. In analysis in the influence of various factors in different geological, PQc geological formation and PQs geological formation, more affected by slope geological formation;P2 geological formation is governed by slope aspect.
In terms of landslide potential analysis, this study used “instability index method” to prediction of the potential hazard of study area. The results in this analysis showed that within the total study area of 3,543 hectares, the highest proportion are in landslide potential # 4(40%~50% )and #5(50%~60%), a total area is about 1,676 hectares and 1,207 hectares, accounts for about 46.8% and 33.7% of the study area.
Bridges, roads and buildings are the targets for soil and water conservation within the study area, Farm road length in high landslide susceptibility area is about 8,832 meters which is 9.2% of the road length in Da-keng.
Buildings located in landslide potential #4(40%~50% )and above is about 28, 1.05% percent of total buildings amount in study area. These buildings are mainly located in northeastern region of Da-keng area.
Water is very important to sustainable development of a given area. For the supply and distribution of water resources in Da-Keng study area, Min-zen and Min-te village have lower Tap-Water supply connection rate in the district. If statistics by individual road, Da-Hu and Chu-keng lane have lower tap-Water supply connection rate about 57.5％and 25.0％. To help the development of the tourism industry in Da-Keng area, it is important that the tap-water connection rate should be upgraded.
In terms of agricultural irrigation assessment , if completing the planning agricultural irrigation systems of Da-keng area can only be completed will with waters from streams. Irrigation could cover the irrigation area of bamboo shoots to 23.7% and 29.4% for irrigation area of citrus products. Irrigation range can even be expanded substantially to 80.6% and 83.3％ with irrigation facilities improvement.
To reduce the danger of landslide occurrence due to high groundwater and searching for alternate sources of water , this study assessed the suitabilities of removing extra water in the ground for use elsewhere downslope to improve agriculture water supply in this area.
This study collect topographic, landform and geological data at 5 study sites in the Da-keng area. Geological logging, resistance physical detection and field check were used to investigate the suitabilities of these 5 sites.
The results show that these 5 sites, 3(#1,#2,#4) were suitable because their geological and topographical conditions are favorable to high groundwater storage.
In groundwater drainage investigation, the highest drainage is 0.00361cms for the site#1 and the lowest is 0.00005cms for site#3. In assessment of the feasibility that use ground water for alternative main source of agricultural water consumption, the highest replacement ratio is 16.79% for the site#1 and the lowest is 1.26% for site#4.
In study on evaluation of low density leisure travel development strategy, it is necessary to take watershed conservation concepts in terms of special geology and environment conditions in Da-Keng area.
Massive disturbance of surface should be avoided for land utilization in the slope land region. To achieve the goal of sustainable land conservation, and a rational land use policies consider land conditions and characteristic should be considered and critically evaluated. All efforts should be made to apply site-specific water and soil conservation measures to reduce geology hazard risk.
In past 20 years, because of Da-keng area did not have specific land use zoning institution in urban planning, there are many arguments in review processes, factors related to geological issue , landscape and building coverage ratio are considered under the existing land development permitted review system.
This study evaluate the draft urban planning using geographical statistics method. In draft urban planning, 80% of residential zone are slope classification #3. Land utilization and construction management in this zone should still be implemented in the future to strengthen the slope land utilization review to avoid potential disaster.
In study on the geological disaster density in each zone during draft urban planning, shallow collapse density that occur in residential zone and scenic zone that allows for construction are relatively low. Although residential zone and scenic zone suspected dip slope landslide disasters density is lower than agricultural zone and protection zone, this disaster is still an important factor that construction will be considered in future.
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