Land-use changes in the periurban interface: Hydrologic consequences on a flatland-watershed scale

Area of Science:

• Hydrology
• Environmental Science
• Geographic Information Systems

Background:

• Peri-urban watersheds are sensitive to land use changes.
• Urbanization and agricultural intensification alter surface runoff and infiltration patterns.
• Understanding these impacts is crucial for water resource management.

Purpose of the Study:

• To analyze the hydrologic effects of land use and land cover changes on surface runoff and infiltration.
• To assess these impacts in the El Pescado Creek watershed, Argentina.
• To model future scenarios of land use change and their hydrologic consequences.

Main Methods:

• Geographic Information System (GIS) techniques were employed.
• The curve-number (CN) method was used to estimate surface runoff.
• Five land-use scenarios (1986–2026) and two rainfall events were analyzed considering antecedent runoff conditions (ARC).

Main Results:

• Land use changes increased CN values and surface runoff, particularly in the upper watershed.
• Conversion to impervious and semi-impervious land cover (urbanization, greenhouses, poultry farms) significantly reduced infiltration.
• Weighted-average infiltration decreased from over 93% to as low as 28.8% depending on rainfall and ARC.

Conclusions:

• Altered infiltration patterns may disrupt natural aquifer recharge processes.
• Hydrologic dynamics within the watershed are being modified by land use changes.
• These changes pose potential risks to water supply for human activities.