Assessing drainage problem areas by GIS: a case study in the eastern Mediterranean region of Turkey

Abstract

Soil productivity is affected by soil physical properties that play a crucial role in planning drainage systems. Improper planning of drainage systems can create high water table problems and, in turn, an unsuitable environment for plant growth. Therefore, drainage systems should be well planned and monitored regularly. It is very labor-intensive and time-consuming to determine the spatial and temporal changes in drainage parameters such as groundwater (GW) depth, elevation, hydraulic gradient and salinity by conventional methods over large areas. Geographic information systems (GIS) can be used to assess the spatial and temporal changes efficiently and rapidly. This study was conducted to determine drainage problem areas and to suggest the most suitable drainage systems for those areas by evaluating spatial and temporal changes in GW depth, elevation and salinity, with regard to drainage criteria used by the State Hydraulic Works (DSI) responsible for the development of land and water resources in Turkey. A pilot area of 8494 ha in the Lower Seyhan Plain, Adana, Turkey, was selected. The elevations and coordinates of 85 drainage observation wells were obtained from the existing maps with a scale of 1/5000 and 1/25 000, respectively. The GW depth and GW salinity data, the latter only available for July, were obtained from an archived long-term monthly data set of the 6th Regional Directorate of the DSI. Running ArcView 3.0a, the salinity, as well as the seasonal maps of the GW depth and elevation, were developed to assess the spatial and temporal changes. Results indicated that about 99.8% of the study area was suffering from various levels of drainage problems. Main, secondary and tertiary drainage canals in the region seemed to be malfunctioning due mostly to siltation and weed problems. GW fluctuation did not seem to be of great importance, indicating a need for a subsurface drainage system. It was concluded that some areas are likely to be prone to potential GW salinization risk during the peak irrigation season if in the future, irrigation water is sparingly used and irrigation efficiency is improved. The GW hydraulic gradient did not significantly change temporally, but it did change spatially.

Mapping multi‐year ground water salinity patterns in irrigation areas using time‐series analysis of ground water salinity maps

“…Different researchers performed various studies on spatial or temporal variation in GWS. Cetin and Diker (2003) used the average of grid pixel values of annual GW maps to observe spatial and temporal change in GWS; Diker et al (1999) compared class areas obtained by classifying annual GWS maps in order to exhibit the temporal change of the GWS. The study by Pebesma and Kwaadsteniet (1997) used a simple regression model for variation over time and for taking location-specific, time-prediction uncertainties into account.…”

Modeling Interaction of Fluid and Salt in an Aquifer/Lagoon System

“…Cetin and Diker (2003) investigated the salinity (total dissolved solids) of ground water in the LSRB and found that the electric conductivity (EC) of shallow ground water in 50.0% of the area was between 0.0 and 0.1 S/m, while EC was between 0.1 and 0.2 S/m in 45.5% of the area and more than 0.2 S/m in the remaining 4.5%. Irrigation water has slightly lower EC than shallow ground water.…”

Spatial and Temporal Evaluation of Depth and Salinity of the Groundwater in a Large Irrigated Area in Southern Turkey

“…Excess irrigation, especially during peak irrigation season, decreased groundwater EC. Spread of the areas, where groundwater salinity were higher than 5 dS m -1 which is considered as the critical EC level for drainage engineering work (Cetin and Ozcan, 1999;Cetin and Kirda, 2003;Cetin and Diker, 2003), was 19.2% in May, 17.7% in July, and 15.5% in October (Fig. 8).…”

“…In the case that groundwater level rises and reaches plant root-zone, even during a drought period prevails, the groundwater rise must be attributed to excess irrigation. In such conditions, irrigation efficiency must be low due to inferior irrigation technique used (Cetin and Diker, 2003). Groundwater level and salinity can be monitored via 3-4 m deep drainage observation wells in planted or nonplanted farm lands.…”