Assessment of a newly implemented irrigated area (Lerma Basin, Spain) over a 10-year period. II: Salts and nitrate exported

Merchán, Daniel; Causapé, J.; Abrahão, Raphael; García-Garizábal, I.

doi:10.1016/j.agwat.2015.04.019

Cited by 19 publications

(24 citation statements)

References 39 publications

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“…The population has also increased, from approximately 40,000 people living around the floodplain in 1982 [63] to approximately 198,000 people in 2016 [59]. Water from return flows and tailwaters from irrigation schemes and mining activities often contains high levels of total dissolved solids (TDS), including the dissolved cations calcium, magnesium, sodium and potassium, and anions such as sulphates, chlorides, fluoride, nitrate, bicarbonate and carbonate [91] and numerous other agro-pollutants leached from soils [35,[92][93][94][95]. Merchán et al [94] also determined that the main causes for increased salinity in the Lerna Basin in Spain were inputs from irrigation water.…”

Section: Discussionmentioning

confidence: 99%

“…Water from return flows and tailwaters from irrigation schemes and mining activities often contains high levels of total dissolved solids (TDS), including the dissolved cations calcium, magnesium, sodium and potassium, and anions such as sulphates, chlorides, fluoride, nitrate, bicarbonate and carbonate [91] and numerous other agro-pollutants leached from soils [35,[92][93][94][95]. Merchán et al [94] also determined that the main causes for increased salinity in the Lerna Basin in Spain were inputs from irrigation water. Similarly, research has found that increased water alkalinity and salinity in the Crocodile River catchment in South Africa was due to anthropogenic pollution, including inputs from agricultural and mining return flows [35,83] The present study found the lower Pongolo River to have historically been poorer in nutrients just downstream of the dam than either above the dam or within NGR.…”

Section: Discussionmentioning

confidence: 99%

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Long-Term Water Quality Patterns of a Flow Regulated Tropical Lowland River

Necker

Neswiswi

Greenfield

et al. 2019

Water

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Floodplain ecosystems in Africa are under threat due to direct anthropogenic pressure and climate change. The lower Phongolo River and associated floodplain is South Africa's largest inland floodplain ecosystem and has been regulated by the Pongolapoort Dam since the 1970s. The last controlled flood release from the dam occurred in December 2014, after which a severe drought occurred and only a base flow was released. The central aims of this study were to determine the historic and present water quality state of the middle and lower Phongolo River and assess the possible effects of the most recent drought may have had. Historic water quality data (1970s to present) were obtained from monitoring stations within the Phongolo River catchment to assess the long-term water quality patterns. Using multivariate statistical analyses as well as the Physicochemical Driver Assessment Index (PAI), a water quality index developed for South African riverine ecosystems, various in situ and chemical water variables were analysed. Key findings included that the water quality of the middle and lower Phongolo River has degraded since the 1970s, due to increased salinity and nutrient inputs from surrounding irrigation schemes. The Pongolapoort Dam appears to be trapping nutrient-rich sediments leading to nutrient-depleted water entering the lower Phongolo River. The nutrient levels increase again as the river flows through the downstream floodplain through input from nutrient rich soils and fertilizers. The drought did not have any significant effect on water quality as the PAI remained similar to pre-drought conditions.Water 2020, 12, 37 2 of 22 impacts on the environment, as well as on the biophysical characteristics of a river both downstream and upstream of the impoundments [7][8][9][10]. Effects include altering the magnitude and velocity of floods and river flows either upstream or downstream of the dam [11], sediment trapping within the impoundment [10,12,13], loss of fertile topsoil downstream of the dam [8,14], nutrient retention within the impoundment [13], nutrient loading downstream of the dam and loss of biodiversity, particularly fish and macroinvertebrates [9,15,16]. The type and magnitude of these effects may differ between systems and is highly dependent on the size of the dam, whether hyper-or hypolimnetic discharge occurs, the purpose for which it was built, the type of river it is located on and the natural variability and function of rivers [12,17,18]. Through controlled flooding regimes, water may be released from an impoundment in a variety of patterns that differ from the natural hydrological regime of a river and thus impacts on the downstream ecosystem [12,[19][20][21], the most prominent impact being reduced downstream flow [8,22]. Reduced river discharge may result in a reduced flooding area and environmental flow, leading to variation in natural abiotic and biotic processes [23] such as nutrient cycling and the migration and spawning of fish [8,24].Low-flow drought disturbances are either seasonal or su...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Long-Term Water Quality Patterns of a Flow Regulated Tropical Lowland River

Necker

Neswiswi

Greenfield

et al. 2019

Water

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“…On the other hand, the amount of irrigation return flows is controlled by the lack or existence of irrigation, and the system and/or management of irrigation carried out. In this sense, higher irrigation efficiencies have been related to lower salt loading (e.g., García-Garizábal and Causapé, 2010;Merchán et al, 2015c).…”

Section: Agricultural Pollution Dynamics In Irrigated Areas In Contramentioning

confidence: 99%

“…However, leached salts will reach water bodies downstream, affecting its quality for human consumption or ecosystem uses (Nielsen et al, 2003). The amount of salts leached depends on different factors such as climate, hydrogeological conditions or irrigation management (Merchán et al, 2015c).…”

Section: Introductionmentioning

confidence: 99%

Runoff, nutrients, sediment and salt yields in an irrigated watershed in southern Navarre (Spain)

Merchán

Casalí

Lersundi

et al. 2018

Agricultural Water Management

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The environmental impact of irrigated agriculture on water quality was assessed in Landazuria watershed (Navarre, northeast Spain), a 479.5 ha watershed with 53% of irrigated agricultural land. In the framework of a long-term monitoring program, precipitation and discharge were measured at 10-minutes intervals and compound daily water samples were collected during the agricultural years (September to August) 2007-2016, and analysed for nitrate (NO 3-), phosphate (PO 4 3-), sediment and total dissolved solids (TDS) concentrations. Typical agricultural management (including crop surfaces, irrigation and fertilization rates) was obtained from inquiries to farmers. Concentration and yield of the studied variables presented a high degree of variation, both intra-and inter-annual. Median concentration for the entire study period were 185, <0.

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“…In the central Ebro valley, several of those basin-wide studies have been conducted for Bárdenas irrigation district (including, for instance, the Lerma and Arba basins [3][4][5][6][7][8][9][10]) and for Riegos del Alto Aragón irrigation district, RAAID (which includes the Irrigation Community of LASESA-an acronym formed by the addition of the first two letters of the three villages LAstanosa, SEna and SAriñena where the irrigated district is located [11][12][13], Del Reguero basin [14], Flumen basin [15], Valcuerna gully [16,17] and La Violada, discussed below). In these studies, different values of irrigation efficiency and water drainage chemistry have been reported under diverse irrigation systems.…”

Section: Introductionmentioning

confidence: 99%

Water Balance and Nitrate and Salt Exports from a Saline–Sodic Irrigation District in Castelflorite (Huesca, NE Spain)

2020

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In the current context of climate change, there is growing interest in the optimization of water management in irrigated areas, in semi-arid environments. The design of adequate adaptation and mitigation measures requires specific data at different scales of the water management hierarchy, up to basin level. In this work, the irrigation and drainage system of San Pedro de Castelflorite Irrigation Community (Huesca province, NE Spain), first set up as a flood irrigation system around 1970 and then modernized to sprinkler irrigation around 2008, was studied over two irrigation seasons. The land in this basin, with a surface of 11,450 ha, is affected by severe sodicity problems, which impedes cultivation in large areas. Most of the drainage water discharges into Clamor Vieja ravine, in which the quantity and quality of drainage, using water, salt, and nitrogen balances, were monitored. The water regime was found to be essentially regulated by irrigation. From the water balance, the consumed and the recoverable fractions were estimated at 76% and 23%, respectively, and the depleted beneficial fraction for the irrigated area at 73%. A predominance of salt dissolution processes over precipitation processes was found, with salt exports of approximately 2000 kg ha−1·year−1. The nitrogen exported by the drainage water was 7 kg N·ha−1·year−1. This value, remarkably lower than those reported for nearby basins in the central Ebro valley, can be attributed to the flooding of rice fields and to the low permeability of the soils present in this basin, which would hamper nitrate washing through the soil profile.

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Assessment of a newly implemented irrigated area (Lerma Basin, Spain) over a 10-year period. II: Salts and nitrate exported

Cited by 19 publications

References 39 publications

Long-Term Water Quality Patterns of a Flow Regulated Tropical Lowland River

Long-Term Water Quality Patterns of a Flow Regulated Tropical Lowland River

Runoff, nutrients, sediment and salt yields in an irrigated watershed in southern Navarre (Spain)

Water Balance and Nitrate and Salt Exports from a Saline–Sodic Irrigation District in Castelflorite (Huesca, NE Spain)

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