Akademik Veri Yönetim Sistemi
30th International Cartographic Conference (ICC 2021), FLORANSA, İtalya, 14 - 18 Aralık 2021, cilt.3, sa.149, ss.1-2
Hydromorphology is an umbrella discipline that examines and evaluates the physical, hydrological and morphological
properties of water bodies and the processes underlying these properties. European Council (EC) has designed the water
framework directive (WFD), one of the centerpiece documents of EC water legislation, to build sustainable water
management (European Commission, 2000). Water quality, quantity, and water ecosystems are entirely interconnected.
The hydromorphological data recorded to explain the state of the water source reveal the differences between assessment
categories. The European Committee has put forward a detailed list of features recorded along the stream, riverbanks,
riparian areas, and floodplains for standardization (CEN, 2002).
A proper understanding of the hydromorphological alterations in rivers through time is critical for scientists,
policymakers, and managers conducting river management activities. The European countries have developed and used
several hydromorphological monitoring and assessment methods with notable differences in aims, approaches, indicators,
and collected data. Each technique provides descriptive information evaluating deviations from a natural state. Historical
data, expert observations, modelling studies, and theoretical researches are used to reveal the natural form known as a
reference condition of a water resource (Rinaldi et al., 2013). The reference condition that reflects the completely or
rarely disturbed state must be explained to reveal the hydromorphological changes. Where field measurement data
representing the reference condition are available, they should be considered first. However, it is difficult to perform field
surveys due to their diverse characteristics and sizes in a high number of catchments. Therefore, the field survey is
followed by historical topographic data sources, orthophotos and aerial photographs. Topographic maps are effective data
sources to investigate river dynamics over a natural fluvial system spatially and temporally. In addition, official
topographic maps at medium scale such as 1:24K or 1:25K have been produced and available for many countries for a
long time. This study aims to reveal the hydro-morphological role of topographical maps that provide information about
river geometry, land use, and artificial/natural features on the river, such as roads, buildings, lakes, or landforms. It was
carried out using Turkish standard topographic maps of five different years between 1957 and 2018 at scale 1:25K. The
selected study area is the Kocaeli-Gebze region in Turkey, which has been the center of industrialization and urbanization
over the years. First, the factors affecting river hydromorphology in the study area were determined. Then, whether each
of these factors can be obtained from topographic maps was examined one by one and features recorded along the river
corridor were extracted. Approximately 82% of the recorded details and related reference conditions were obtained thanks
to the spatial evaluations made for the selected study site using 1:25K topographic maps, which are more advantageous
than time-consuming field studies and expensive satellite images. This result has shown that widely available current and
old topographic datasets are an effective tool to reduce the number of field surveys conducted during hydromorphological
studies.