Raising surface water levels in peat areas with dairy farming

2010 ◽  
Vol 97 (11) ◽  
pp. 1887-1897 ◽  
Author(s):  
J.A. de Vos ◽  
P.J.T. van Bakel ◽  
I.E. Hoving ◽  
R.A. Smidt
Author(s):  
Jantine Hoekstra ◽  
Annette van Schie ◽  
Henk A. van Hardeveld

Abstract. Reducing soil subsidence caused by peat oxidation is a major challenge in the Dutch peatlands. To maintain suitable conditions for dairy farming water levels are periodically lowered to keep pace with soil subsidence. Consequently, soil subsidence continues, causing increasing water management costs. We experimented with pressurized drainage in Polder Spengen, a peatland polder in the west of the Netherlands that is primarily used for dairy farming. In this polder, surface water levels of 40 cm below ground surface are maintained, which results in average soil subsidence rates of 7 mm yr−1. Pressurized drainage is a novel technique to reduce soil subsidence, it uses field drains that are connected to a small water basin. Surface water can be pumped in or out the water basin, which enables active manipulation of the pressure head in the field drains. The objective of this study is to implement this technique into practice and determine its effect on groundwater tables, soil subsidence rates, and water demand. We applied pressurized drainage in 55 ha of peatland meadows in Polder Spengen, distributed over seven farms. We monitored groundwater tables, surface elevation and water demand. Preliminary results show that during the extreme dry summer of 2018, groundwater tables could be maintained at 40 cm below ground surface, which is 60 cm higher compared to locations without pressurized drainage. This reduced soil subsidence by 50 %. Throughout the entire summer of 2018, the water demand amounted to 3–5 mm d−1. We believe the technique can effectively contribute to minimize soil subsidence, but relatively high implementation costs may be a barrier to large-scale implementation.


2012 ◽  
Vol 16 (3) ◽  
pp. 649-669 ◽  
Author(s):  
G. H. de Rooij

Abstract. The increasing importance of catchment-scale and basin-scale models of the hydrological cycle makes it desirable to have a simple, yet physically realistic model for lateral subsurface water flow. As a first building block towards such a model, analytical solutions are presented for horizontal groundwater flow to surface waters held at prescribed water levels for aquifers with parallel and radial flow. The solutions are valid for a wide array of initial and boundary conditions and additions or withdrawals of water, and can handle discharge into as well as lateral infiltration from the surface water. Expressions for the average hydraulic head, the flux to or from the surface water, and the aquifer-scale hydraulic conductivity are developed to provide output at the scale of the modelled system rather than just point-scale values. The upscaled conductivity is time-variant. It does not depend on the magnitude of the flux but is determined by medium properties as well as the external forcings that drive the flow. For the systems studied, with lateral travel distances not exceeding 10 m, the circular aquifers respond very differently from the infinite-strip aquifers. The modelled fluxes are sensitive to the magnitude of the storage coefficient. For phreatic aquifers a value of 0.2 is argued to be representative, but considerable variations are likely. The effect of varying distributions over the day of recharge damps out rapidly; a soil water model that can provide accurate daily totals is preferable over a less accurate model hat correctly estimates the timing of recharge peaks.


1994 ◽  
Vol 126 (S169) ◽  
pp. 7-20 ◽  
Author(s):  
Dale H. Vitt

AbstractCanadian peatlands can be classified into ombrotrophic bogs and minerotrophic fens, the latter subdivided into poor, moderate-rich, and extreme-rich fens, each with distinctive indicator species, acidity, alkalinity, and base cation content. If hydrology is considered the most important factor in peatland classification then the primary division must be between ombrotrophic bogs and minerotrophic fens; however both chemical and vegetational differences strongly indicate that the primary division of peatlands should be between acidic, Sphagnum-dominated bogs and poor fens on the one hand, and alkaline, brown-moss-dominated rich fens on the other. Although some metals such as sulphur and aluminum also vary along this gradient, nutrient contents of the surface waters do not. Bogs and fens are oligotrophic to mesotrophic wetlands that should be distinguished from eutrophic, non-peat-forming wetlands such as marshes and swamps by the presence in the former of a well-developed ground layer of bryophytes associated with relatively little seasonal water level fluctuation. Oligotrophy is probably maintained in bogs and poor fens by reduced water flow, whereas rich fens maintain mesotrophy by having larger water through-puts; however this is not well documented. Sphagnum appears to have real ecological significance, both in the initial stages of acidification and in controlling surface water temperature. Seasonal variation in surface water chemistry in all peatland types is relatively small, however precipitation events leading to changes in water levels do affect some chemical components. Although both autogenic and allogenic factors affect peatland development, initiation of peat formation and early development of peatlands during the Early and Mid Holocene were considerably influenced by regional climatic change. Later developmental patterns during the late Holocene and those seen at the present time appear to be more influenced by autogenic factors.


2010 ◽  
Vol 13 (4) ◽  
pp. 741-759
Author(s):  
L. De Doncker ◽  
P. Troch ◽  
R. Verhoeven ◽  
K. Buis ◽  
P. Meire

The 1D model package STRIVE is verified for simulating the interaction between ecological processes and surface water flow. The model is general and can be adapted and further developed according to the research question. The hydraulic module, based on the Saint-Venant equations, is the core part. The presence of macrophytes influences the water quality and the discharge due to the flow resistance of the river, expressed by Manning's coefficient, and allows an ecological description of the river processes. Based on the advection–dispersion equation, water quality parameters are incorporated and modelled. Calculation of the water quantity parameters, coupled with water quality and inherent validation and sensitivity analysis, is the main goal of this research. An important study area is the River Aa near Poederlee (Belgium), a lowland river with a wealth of vegetation growth, where discharge and vegetation measurements are carried out on a regular basis. The developed STRIVE model shows good and accurate calculation results. The work highlights the possibility of STRIVE to model flow processes, water quality aspects and ecological interaction combined and separately. Coupling of discharges, water levels, amount of biomass and tracer values provides a powerful prediction modelling tool for the ecological behaviour of lowland rivers.


Author(s):  
Isolde S. Barkow ◽  
Sascha E. Oswald ◽  
Hermann-Josef Lensing ◽  
Matthias Munz

Abstract Bank filtration is considered to improve water quality through microbially mediated degradation of pollutants and is suitable for waterworks to increase their production. In particular, aquifer temperatures and oxygen supply have a great impact on many microbial processes. To investigate the temporal and spatial behavior of selected organic micropollutants during bank filtration in dependence of relevant biogeochemical conditions, we have set up a 2D reactive transport model using MODFLOW and PHT3D under the user interface ORTI3D. The considered 160-m-long transect ranges from the surface water to a groundwater extraction well of the adjacent waterworks. For this purpose, water levels, temperatures, and chemical parameters were regularly measured in the surface water and groundwater observation wells over one and a half years. To simulate the effect of seasonal temperature variations on microbial mediated degradation, we applied an empirical temperature factor, which yields a strong reduction of the degradation rate at groundwater temperatures below 11 °C. Except for acesulfame, the considered organic micropollutants are substantially degraded along their subsurface flow paths with maximum degradation rates in the range of 10−6 mol L−1 s−1. Preferential biodegradation of phenazone, diclofenac, and valsartan was found under oxic conditions, whereas carbamazepine and sulfamethoxazole were degraded under anoxic conditions. This study highlights the influence of seasonal variations in oxygen supply and temperature on the fate of organic micropollutants in surface water infiltrating into an aquifer.


2019 ◽  
Vol 11 (24) ◽  
pp. 7050 ◽  
Author(s):  
Sherien Abdel Aziz ◽  
Martina Zeleňáková ◽  
Peter Mésároš ◽  
Pavol Purcz ◽  
Hany Abd-Elhamid

Several studies have reported that the construction of the Grand Ethiopian Renaissance Dam (GERD) could have severe effects on the water resources in downstream countries, especially Egypt. These effects include changes in surface water level, groundwater levels in shallow and deep aquifers, saltwater intrusion, and increases in soil salinity, which could affect crop yields. This paper assesses the potential impacts of the GERD on the Nile Delta, Egypt. It includes the effects of reducing surface water levels (SWL) and changing the crop patterns at the groundwater levels (GWL), in addition to the effect of cultivating crops that consume less water on soil salinity. A pilot area is selected in the east of the Nile Delta for the assessment. The results of the study revealed that GWL is directly proportional to SWL. Comparing the case study of 2012, when SWL was reduced by 50%, the GWL decreased from 5.0 m to 2.0 m. After adjustment, the crop patterns from rice to other crops decreased the GWL to 1.30 m. Additionally, the results showed that there is a significant relationship between soil salinity and crop patterns. Soil salinity increased during the cultivation of the Delta with non-rice crops, such as grapes. Salinity increased from 0.45 S/m after 10 years of simulation to 0.48 S/m. This estimation highlights the undesirable effects of the GERD on Egypt’s water resources, soil salinity, crop yields, and national income.


2020 ◽  
pp. 161-199
Author(s):  
Nadhir Al-Ansari ◽  
Sabbar Saleh ◽  
Twana Abdullahand ◽  
Salwan Ali Abed

Insufficiency of water resources in the Middle East Region represents vital factors that influence the stability of the region and its progress. Expectations indicate that the condition will be dimmer and more complicated, especially in Iraqi territory. Iraq, which is situated in the Middle East, it covers an area of 433,970 square kilometers and populated by about 32 million inhabitants. Iraq greatly relies in its water resources on the Tigris and Euphrates Rivers as a surface water resources, and several productive groundwater aquifers in which from the hydrogeological point of view divided into several major aquifer units including Foothill, Al-Jazira, Aquifer System, Mandali-Badra-Teeb, Mesopotamian and Desert Aquifer system. Recently, Iraq is suffering from water shortage problems. This is due to external and internal factors affecting the water quality of water resources; they are controlled and uncontrolled factors. The uncontrolled factors are climate change and its consequences, such as reduction of precipitation and temperature increasing. The controlled factors have a significantly negative influence on water resources, but their effects involve more specific regions. The controlled factors are mainly represented by building dams and irrigation projects within the upper parts of the Tigris and Euphrates catchments, Al-Tharthar Scheme, waste water, solid wastes and wastes from wars, which has a significant effect on surface water in Iraq because about 80% of the water supply to Euphrates and Tigris Rivers come from Turkey. In addition, the pressures resulting from the high demand for water resources, and the continued decline in their quantity rates have led to major changes in the hydrological condition in Iraq during the past 30 years. The decrease in surface water levels and precipitation during these three decades reflects the drop in the levels of water reservoirs, lakes, and rivers to the unexpected levels. The level of main country’s water source, Tigris, and Euphrates Rivers has fallen to less than a third of its natural levels. As storage capacity depreciates, the government estimates that its water reserves have been reduced precariously. According to the survey from the Ministry of Water Resources, millions of Iraqi people have faced a severe shortage of drinking water. Since of the importance of water for human life and the need to monitor temporal and spatial changes in quality and quantity, there is a need to develop a general Iraqi Water Quality Index (Iraq WQI) to monitor surface water and groundwater and classify it into five categories, very good, good, acceptable, bad and very bad, in terms of suitability for domestics, irrigation and agriculture depending on the Iraqi and WHO standards for drinking water. In addition, strict establishment for the regular quantitative monitoring surface water and groundwater setting and processes. Prospects are more negative for all riparian countries. This implies that solving these problems requires actual and serious international, regional, and national cooperation to set a prudent plan for water resources management of the two basins. Iraq being the most affected country should seriously set a prudent, scientific, and strategic plan for the management and conservation of its water resources. Keywords: Pollution, Water Quality, Waste, Surface water, Groundwater, Iraq.


2018 ◽  
Author(s):  
Tim Busker ◽  
Ad de Roo ◽  
Emiliano Gelati ◽  
Christian Schwatke ◽  
Marko Adamovic ◽  
...  

Abstract. Lakes and reservoirs are crucial elements of the hydrological and biochemical cycle and are a valuable resource for hydropower, domestic and industrial water use and irrigation. Although their monitoring is crucial in times of increased pressure on water resources by both climate change and human interventions, publically available datasets of lakes and reservoir levels and volumes are scarce. Within this study, a time series of variation in lake and reservoir volume between 1984 and 2015 were analysed for 135 lakes over all continents by combining the JRC Global Surface Water (GSW) dataset and the satellite altimetry database DAHITI. The GSW dataset is a highly accurate surface water dataset at 30 m resolution compromising the whole L1T Landsat 5, 7 and 8 archive, which allowed for detailed lake area calculations globally over a very long time period using Google Earth Engine. Therefore, the estimates in water volume fluctuations using the GSW dataset are expected to improve compared to current techniques as they are not constrained by complex and computationally intensive classification procedures. Lake areas and water levels were combined in a regression to derive the hypsometry relationship (dh/dA) for all lakes. Nearly all lakes showed a linear regression, and 42 % of the lakes showed a strong linear relationship with an R2 > 0.8 and an average R2 of 0.91. For these lakes and for lakes with a nearly constant lake area (coefficient of variation 


2021 ◽  
Author(s):  
◽  
Craig Wayne Allen

<p>Te Hapua is a complex of small, privately owned wetlands approximately 60 km northwest of Wellington. The wetlands represent a large portion of the region's remaining palustrine swamps, which have been reduced to just 1% of the pre-1900 expanse. Whilst many land owners have opted to protect wetlands on their land with covenants, questions have been raised regarding potential threats stemming from the wider region. Firstly, some regional groundwater level records have shown significant decline in the 10 to 25 years they have been monitored. The reason for this is unclear. Wetlands are commonly associated with groundwater discharge, so a decline in groundwater level could adversely affect wetland water input. Secondly, estimated groundwater resources are currently just 8% allocated, so there is potential for a 92% increase in groundwater abstraction from aquifers that underlie the wetlands. Finally, predictions of future climate change indicate changes in rainfall quantity and intensity. This would likely alter the hydrological cycle, impacting on rainfall dependant ecosystems such as wetlands as well as groundwater recharge. Whilst previous ecological surveys at Te Hapua provide valuable information on biodiversity and ecological threat, there has been no detailed study of the hydrology of the wetlands. An understanding of the relationship between the surface water of the wetlands and the aquifers that underlie the area is important when considering the future viability of the wetlands. This study aims to define the local hydrology and assess the potential threat of 'long term' groundwater level decline, increased groundwater abstraction and predicted climate change. Eleven months of water level data was supplied by Wellington Regional Council for three newly constructed Te Hapua wetland surface water and adjacent shallow groundwater monitoring sites. The data were analysed in terms of their relative water levels and response to rainfall. A basic water balance was calculated using the data from the monitoring sites and a GIS analysis of elevation data mapped the wetlands and their watersheds. A survey of 21 individual wetlands was carried out to gather water quality and water regime data to enable an assessment of wetland class. Historical groundwater level trends and geological records were analysed in the context of potential threat to the wetlands posed by a decline in groundwater level. Climate change predictions for the Kapiti Coast were reviewed and discussed in the context of possible changes to the hydrological cycle and to wetlands. Results from the wetland survey indicated that there are two distinct bands of wetlands at Te Hapua. Fens are found mostly in the eastern band and are more likely to be discharge wetlands, some of which are ephemeral. Swamps are found mostly in the western band and are more likely to be recharge wetlands. Dominant water input to fens is via local rainfall and local through-flow of shallow groundwater, especially from surrounding dunes. The eastern band of wetlands is typified by higher dunes and hence has greater input from shallow groundwater than wetlands in the western band. Dominant water input to swamps is via local rainfall, runoff, and through-flow from the immediate watershed and adjacent wetlands. Overall, the future viability of the Te Hapua wetland complex appears promising. Historical groundwater declines appear to be minimal and show signs of reversing. Abstraction from deep aquifers is not likely to impact on wetland water levels. Climate change is likely to have an impact on the hydrological cycle and may increase pressure on some areas, especially ephemeral wetlands. The effect of climate change on groundwater level is more difficult to forecast, but may lower water level in the long term.</p>


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