Weaponizing Water: Damming the North Crimean Canal

Water security is a matter of increasing global concern due to pressures induced by drying climate trends and the impact water shortages have on human populations, ecosystems, and economic productivity (Grey and Sadoff, 2007). The availability of a stable and reliable source of fresh water is essential for maintaining human well-being and economic development and is particularly important in regions that rely on agriculture as the primary industry.

The North Crimean Canal (NCC) is a major piece of infrastructure in southern Ukraine that transfers fresh water from the Dnieper River to the Crimean Peninsula. The canal was constructed from 1961 to 1971, with the final main canal extending a total length of 402.6 km (Tymchenko, Z. 2012) (Figure 1). The water transferred by the canal accounts for 85% of the peninsulas fresh water supply and is stored in reservoirs and distributed by a 1,534 km network of smaller canals which directly service towns and agricultural areas across the region (Tymchenko, Z. 2012, Roerink and Zhovtonog, 2005).

Water supplied by the canal is primarily used for agriculture (83%), which is the main industry of Crimea (Figure 2). Due to unreliable rainfall, up to 357,200 hectares of agricultural land is equipped with irrigation infrastructure (Roerink and Zhovtonog, 2005). Following the annexation of Crimea by Russia in February 2014 and citing outstanding payments on water delivered by the canal by Russia, the Ukrainian Government constructed a dam across the canal north of the border with Crimea, reducing the flow from 85 m ³ /sec to 4 m ³ /sec (RT News, 201). Following the invasion of Ukraine in February 2022, Russian forces destroyed the dam using explosives, resuming the supply of water to the Peninsula (Water went to Crimea, 2022).

The damming of the NCC induced a severe water shortage on the Crimean Peninsula, impacting irrigated agriculture and public water supply availability (Kayukova and Yurovsky, 2015). The objective of this analysis is to quantify the impact of this water shortage on irrigated agriculture using a Normalized Difference Vegetation Index (NDVI) and change analysis. Land cover classification using NDVI simplifies the interpretation of vegetation distribution and condition (Meera Gandhi et al 2015). Understanding the impacts of anthropogenically induced water shortages may be useful for informing laws and conventions that address the use of water as a socioeconomic weapon.

Remote sensing of land surface vegetation cover in agricultural areas using a NDVI is a well understood method for measuring crop health and productivity (Sruthi and Aslam, 2015). A key factor affecting agricultural performance is the availability of water during the growing season. The aim of this study is to use Landsat 8 imagery to generate an NDVI at two time points to quantify the impact of the removal of the NCC water supply on irrigated agriculture in the Perekopskyi region in Northern Crimea. This region is host to a significant proportion of the peninsulas rice cultivation, which is heavily reliant on irrigation water and consumes up to 60% of the fresh water supplied by the canal (Kayukova and Yurovsky, 2015). The regional NDVI will then be used to conduct a change analysis between the two time points to determine the change in area of irrigated agricultural land.

The study area is defined by the Perekopskyi administrative region of Northern Crimea, covering an area of 2476 km ²  (Figure 3). The main NCC passes through the northeast of the region and a distribution canal known as the Razdolnensky Rice Canal transfers water throughout the agricultural districts.

Landsat 8 OLI/TIRS Collection Level 2 Surface reflectance data for path 178 and row 028 were extracted from the USGS Earth Explorer data portal. The images selected cover the entire Perekopskyi region and contain less than 5% cloud cover within the area of interest (Figure 4). The 30m pixel resolution provided by the Landsat 8 data was sufficient in resolving the agricultural features of interest to an appropriate level of detail. The initial observation period is August 2013, which was the last summer growing season prior to the removal of the canal water supply in February 2014.  The second observation period is August 2021, which is seven years after the removal of the canal water supply and represents a point of maximum water stress in the region following a period of prolonged drought and regional water shortage. The Level 2 surface reflectance data has been corrected for spatial and temporal scattering caused by gasses and particulates in the atmosphere. Utilising Landsat 8 data for both observation periods reduce the potential for error due to the identical method of data acquisition and processing of each image.