A pilot study for water storage and carbon variability in an irrigation pond of the Southeastern Plains, USA

Authors: ALBRIGHT, ANDREA - Orise Fellow; Coffin, Alisa; Pisani, Oliva; Bosch, David; Strickland, Timothy

Submitted to: Journal of the American Water Resources Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/26/2025
Publication Date: 6/4/2025
Citation: Albright, A.T., Coffin, A.W., Pisani, O., Bosch, D.D., Strickland, T.C. 2025. A pilot study for water storage and carbon variability in an irrigation pond of the Southeastern Plains, USA. Journal of the American Water Resources Association. 61(3):e70026. https://doi.org/10.1111/1752-1688.70026.
DOI: https://doi.org/10.1111/1752-1688.70026

Interpretive Summary: Farm ponds are a common feature of many areas of food production, because they provide a ready source of water for growing plants. At the same time, most small ponds have been left out of many data sets even though there are many ponds throughout the world. In this study, the pond contains water from both rainfall and water that was pumped out of the ground into the pond. The changes to dissolved organic carbon (DOC) in ponds is not well understood at present, and samples of the pond water were taken throughout 2022 in order to study those differences. Although lakes are visible from satellite photos, many farm ponds are too small to be visible in fine detail, and a small Uncrewed Aerial System (UAS) or drone was used to inspect the pond from above to learn the shape and volume of the pond. Measurements of the pond throughout the year show that the amount of water that drains into the ponds is used almost entirely to water the fields nearby, and that the pond size is one quarter of these inputs and outputs. The water samples show that DOC is affected by water draining into the pond in the first part of the year, and then is more affected by processes occurring in the pond in response to leaves falling later in the year. A combined model of the pond bottom plus the surrounding landscape can be used to find the total volume of the pond when the water surface height is known. These measurements all contribute to a greater understanding of farm ponds similar to this one.

Technical Abstract: Farm ponds are an ubiquitous feature of many agricultural landscapes due to their use for crop irrigation. And yet, most small water bodies have been ignored as reservoirs of water storage, carbon sources and sinks, despite their large number in the global landscape. Ponds at first glance are assumed to contain surface water from precipitation and surface runoff, but deep groundwater was also being pumped into an irrigation pond to maintain a water supply for irrigation. Dissolved organic carbon (DOC) fluctuations in such ponds are poorly understood, and water quality measurements were taken in 2022 to quantify and characterize DOC. Additionally, ponds can be difficult to study using satellite images due to their size relative to image resolution, and small Uncrewed Aerial System (UAS)-mounted optical imagery and photogrammetrically derived products were used to assist in characterizing a farm pond. In this study, an irrigation pond was found to have a storage volume of 50,770 m^3. DOC samples ranged from 1.77 to 19.9 mg/L, in addition dissolved organic matter (DOM) indices reveal a shift from terrestrial-derived DOM sources earlier in the year to more microbial-derived ones later on. And a fused topobathy surface that models storage volumes over a typical crop year. Together this study presents an integrated analysis of a typical irrigation pond in South Georgia that analyzes water inputs and withdrawals, quantifies DOC and characterizes DOM, and models pond storage volumes.