Water Count Time Series - Landsat, DETSI Algorithm, Queensland 

This dataset indicates the presence and persistence of water across Queensland between 1988 and 2022. Water is one of the world’s most important resources as it’s critical for human consumption, agriculture, the persistence of flora and fauna species and other ecosystem services. Information about the spatial distribution and prevalence of water is necessary for a range of business, modelling, monitoring, risk assessment, and conservation activities. The water count product is based on water index and water masks for Queensland (Danaher & Collett 2006) and represents the proportion of observations with water present across the Landsat time series as a fraction of total number of possible observations for the period 1 Jan 1988 to 31 Dec 2022. The product has two bands where band 1 is the number of times water was present across the time series, and band 2 is the count of unobscured (i.e. non-null) input pixels, or number of total observations for that pixel. Cloud, cloud-shadow, steep slopes and topographic shadow can obscure the ability to count water presence. 

We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging. U.S. Geological Survey (USGS) provided the Landsat imagery. 

The maps are intended for rural landscapes and are suited to many applications including: - property planning - local government planning - flood risk assessment and management - habitat identification and mapping - analyses of potential biodiversity refugia - analyses of landscape change and resilience. 

Water mask - The automatic water mask available for detecting water and non-water signatures from Landsat satellite imagery for a single date. Water presence/absence is assessed for each 30 m Landsat pixel. This is the primary product used to develop the water count and water prevalence products, which are based on the Landsat time series (1 Jan 1989 to 31 Dec 2021). Water count - The water count product is calculated, per pixel, as the sum of number of observations with water present across the Landsat time series as a fraction of total number of possible observations for the period 1 Jan 1989 to 31 Dec 2021. Water prevalence - The water prevalence product is extracted from the water count product and classified by proportions of observations with water present.