Mobile GIS to Assist Soil and Water Conservation
The landform is constantly changing in the world that we live. Every day, various surface processes gradually reshape the terrain in their unique ways, which generally includes mechanical erosion, chemical erosion, and biological weathering. Depending on geological and meteorological conditions in different regions, some processes might be more significant than others. In a mountainous and humid island country like Taiwan, severe surface processes often cause damage to the citizens. Therefore, to ensure the safety of people, Taiwan government has established special agencies to monitor the risk of landslides and debris flow and inspect the land use on appointed mountain slopes regularly.
Challenges & Goals
As mentioned above, to protect the mountain slopes from inappropriate development, Taiwan government has designated agencies for soil and water conservation in both central and local levels. In local government, such special divisions are usually established under Water Resources Bureau and have to conduct various field tasks.
However, in the past, when the field workers of Water Resource Bureau were carrying field inspection, they could only obtain the coordinates of the target area from old GPS devices. Therefore, these spatial data should be brought back to the office and use software for PC to process, which is impossible to stop illegal activities on-the-scene.
With the advancements in geospatial technologies, these problems can be solved with an innovative solution, which is to use a mobile-based surveying system that has integrated GIS and GPS capabilities like SuperSurv 10 developed by Supergeo.
According Soil and Water Conservation Act and Slopeland and Utilization Act, the staff of Water Resources Bureau has the right and the obligation to carry several field works. Three major tasks and their detailed procedures are listed below.
1. Checking a registered construction on the mountain slope:
For an approved development, the field crews will frequently visit the site and use the waypoint function in SuperSurv to check whether the development complies with the plan permitted by the authority.
Also, the temporary road and other facilities will be marked by SuperSurv for confirming if they are built according to the documents sent previously.
To ensure the development will not increase unnecessary risks at all times, officials will continuously repeat these two steps until the construction is completed.
Fig. 1 Overlaying the target area with administrative boundaries
2. Inspecting an unregistered construction on the mountain slope:
Contrarily, if someone develops his mountain slope without approval, the staff of Water Resources Bureau will conduct an on-site inspection after receiving related report.
First, after arriving target area, the officials will activate the GPS positioning function in SuperSurv and collect spatial data of the illegally developed region.
Second, they will overlay these data with online or offline basemap to check how large the illegally utilized area is in detail.
Lastly, the inspectors will import cadastral data to find the information of the landowner. If the land is not developed by the landowner, it will become a crime, and the developer will be prosecuted.
3. Building Retaining Walls or Using Soil Nailing Techniques:
When a slope is very likely to fall or could lead to a great disaster, it is necessary to build retaining walls or implement other techniques to prevent such results. For the field workers of Water Resources Bureau, the first step is to identify the owner of this land. The case will be marked and transferred to other government agencies if that mountain slope belongs to them, which is a simple step that can also be completed by using GPS positioning function in SuperSurv.
Second, if the land owner is local government, the field crews will use the measurement tool to know how big the perimeter and area are. Therefore, the total cost spent on retaining walls and other preventing techniques can be roughly estimated, providing instant information to help the decision makers arrange the budget more properly.
Fig. 2 Using cadastral maps to find out the landowner
Results & Benefits
The traditional GPS devices can only assist you to get the coordinates, which is almost impossible for field workers to stop illegal activities or even impose a fine. After putting SuperSurv into use, the officials of Water Resources Bureau can locate themselves extremely accurately by its GPS function.
Also, users can easily import various basemaps both online or offline to overlay with the collected data to know detailed cadastral information about a certain land.
Moreover, the features like custom forms, waypoint, and GPS tracks are also very practical and useful when users want to capture spatial data or perform the stakeout. By using SuperSurv, the staff of Water Resources Bureau in local government has significantly simplified the workflow and hence boosted their productivity. The result clearly shows the benefits that bring by implementing the latest geospatial technologies into soil and conservation.