Citation: Tseng, K.-H.; Yang, T.-H.;
Chen, P.-Y.; Chien, H.; Chen, C.-F.;
Hung, Y.-C. Exploring the Feasibility
of Mitigating Flood Hazards by an
Existing Pond System in Taoyuan,
Taiwan. Drones 2023, 7, 1. https://
doi.org/10.3390/drones7010001
Academic Editors:
Andrzej Łukaszewicz,
Wojciech Giernacki,
Zbigniew Kulesza, Jaroslaw Pytka
and Andriy Holovatyy
Received: 15 November 2022
Revised: 16 December 2022
Accepted: 16 December 2022
Published: 20 December 2022
Copyright: © 2022 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
Article
Exploring the Feasibility of Mitigating Flood Hazards by an
Existing Pond System in Taoyuan, Taiwan
Kuo-Hsin Tseng
1,2,3,
* , Tsun-Hua Yang
4
, Pei-Yuan Chen
3
, Hwa Chien
3
, Chi-Farn Chen
1
and Yi-Chan Hung
2
1
Center for Space and Remote Sensing Research, National Central University, 300 Zhongda Rd., Zhongli Dist.,
Taoyuan City 32001, Taiwan
2
Department of Civil Engineering, National Central University, 300 Zhongda Rd., Zhongli Dist.,
Taoyuan City 32001, Taiwan
3
Institute of Hydrological and Oceanic Sciences, National Central University, 300 Zhongda Rd., Zhongli Dist.,
Taoyuan City 32001, Taiwan
4
Department of Civil Engineering, National Yang Ming Chiao Tung University, 1001 Daxue Rd., East Dist.,
Hsinchu City 30010, Taiwan
* Correspondence: khtseng@csrsr.ncu.edu.tw
Abstract:
Changes in the global climate have induced densified rainfall and caused natural hazards
across the world in recent years. Formed by a central mountain range and a corridor of alluvial plains
to the west, Taiwan is at risk of flood hazards owing to its low-lying lands as well as the distinct
seasonality of rainfall patterns. The rapid discharge of surface runoff and a growing number of
impervious surfaces have also increased flood hazards during recent typhoon landfalls. A century
ago, ancestors in Taoyuan City constructed a system of water channels composed of thousands of
ponds to fulfill the needs of agriculture and aquaculture. During the expansion of urban areas, land
reformation replaced a majority of earlier ponds with residential and industrial zones. However, the
remaining ponds could potentially serve as on-site water detention facilities under the increasing
risk of floods. In this research, we first renewed an outdated pond database by deploying a novel
unmanned aerial vehicle (UAV) system with a micro-sonar to map the bathymetry of 80 ponds. Next,
a simplified inundation model (SPM) was used to simulate the flood extent caused by different
scenarios of rainfall in Bade District of Taoyuan City. Assuming that extremely that heavy rainfalls at
25, 50, 75, and 100 mm occurred in a very short period, the flood area would decrease by 96%, 75%,
52%, and 37%, respectively, when the ponds were preparatorily emptied.
Keywords: mobile mapping; UAV; sonar; simplified inundation model
1. Introduction
A network of ponds scattered over a 30
×
30 km area is an iconic landscape in northern
Taiwan (Figure 1). The ancient Shihmen river, flowing through the center of current Taoyuan
City and forming the alluvial plain, was captured by the northbound river and reduced
water levels at lower reaches more than 30,000 years ago [
1
]. The ancestors who arrived here
centuries ago had settled along the river bank or areas with accessible groundwater. Along
with the growing population, residents who in the early stage farmed with precipitation
and natural watercourses had to build water facilities in the last century [
2
]. Freshwater
supply had become an issue, so the ancestors irrigated with ponds and ditches. Although
Taoyuan’s geographical environment is unsuitable for dams as the average slope of streams
is 1/40–1/120 [
2
], the soil type composed of laterite and loess is conducive to constructing
artificial water storage facilities. As time went on, some of the ponds functioned as small
reservoirs in the water source management system and were linked with rivers and streams.
These ponds’ functionalities have become an intricate system for irrigation, drainage, wetland
conservation, and aquafarming [3] (Figure 1, inset figures).
Drones 2023, 7, 1. https://doi.org/10.3390/drones7010001 https://www.mdpi.com/journal/drones
