Akademik Veri Yönetim Sistemi
PURE AND APPLIED GEOPHYSICS, cilt.2026, sa.1, ss.1-12, 2026 (SCI-Expanded, Scopus)
This study diagnoses monthly trends in
streamflow magnitude and regime for the Susurluk Basin (Türkiye), which spans
semi-arid and mountainous sub-climates. We analyze monthly records from 1990 to
2019 at 14 stream gauges and nine precipitation stations. Trends are assessed
with the Mann–Kendall (MK) test alongside recent graphical approaches—Improved
Visualization for Innovative Trend Analyses (IV-ITA) to resolve value
class-based (low/high) behavior, and Innovative Polygon Trend Analysis (IPTA)
with the Star Concept to quantify intra-annual transitions. Before the trend
analyses, the stations were tested to determine whether their values were
homogeneous, and any inhomogeneous stations were excluded from the study. The
consistency between the trends of nine precipitation stations and the
streamflow data in the basin was analyzed. Across the basin, the average streamflow
increased by approximately 40–60% between January and March at many measurement
points. However, it then decreased by around 80% in April, albeit at a more
moderate rate in December. This suggests significant rebalancing occurred
during the December–April period, when most of the annual streamflow occurs. IV-ITA
exhibits broadly similar trends for both low and high streamflow classes, with
notable exceptions in January–February. Precipitation–streamflow trend
directions are largely consistent in the high-flow season (December–April),
supporting the notion that climatic control influences the detected shifts. To
contextualize these signals, basin-wide land-use/land-cover shifts
(1990–2018)—notably urban growth, forest expansion, and cropland
reconfiguration—provide process context, indicating that a larger fraction of
rainfall is routed as fast surface runoff while infiltration and base streamflow
recharge decline, alongside seasonally modified water demand. Collectively, the
MK + IV-ITA + IPTA framework reveals class-specific and intra-annual dynamics
that are obscured by monolithic tests alone and provides decision-relevant
evidence for allocation, drought–flood risk, and operations in an intensively
managed basin.