Hydrological modeling in swelling/shrinking peat soils

Camporese, Matteo; Ferraris, Stefano; Putti, Mario; Salandin, Paolo; Teatini, Pietro

doi:10.1029/2005wr004495

Cited by 61 publications

(59 citation statements)

References 32 publications

(84 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the course of the year, several desiccation and re-wetting cycles naturally occur. That is the reason why it is difficult to implement shrinkage characteristics of soils in hydraulic models to enable a better specification of transient hydraulic properties (Camporese et al 2005(Camporese et al , 2006Price 2004, 2005;Smiles 2000). As soon as a new initial shrinkage state occurs, the shrinkage characteristic of the soil itself changes, and the 'old' shrinkage characterisation and consequently also the derived hydraulic properties no longer apply (Baumgartl and Horn 1999).…”

Section: Discussionmentioning

confidence: 97%

Shrinkage processes of a drained riparian peatland with subsidence morphology

2009

View full text Add to dashboard Cite

Purpose The drainage of a riparian peatland interspersed with organic and mineral substrates in Northern Germany has led to subsidence morphology due to mineralisation, initial settlement and shrinkage processes causing cultivation problems and yield declines. To explain the relevancy of shrinkage to changes of the surface morphology and soil properties, organic and mineral substrates were analysed with regard to (1) shrinkage potential (i.e. the maximum shrinkage), (2) shrinkage curve, (3) actual in situ shrinkage and (4) irreversible shrinkage proportions. Materials and methods The investigated substrates are sedge peat, peat-clay, half-bog and alluvial sand of Fibric Limnic Histosols (Drainic) and a glacial clay for comparison. The methods used to obtain the shrinkage curves include the consideration of crack formation due to desiccation, as digital photography and image analysis were used in addition to height change measurements. To characterise the actual in situ shrinkage, continuous records of the soil matric potential for a 4.5-year period at two different intensively drained Histosols (moderately and deeply drained: mean groundwater table 0.6 and 1.7 m under ground level) were accomplished in four depths (15, 40, 70, 100 cm). Results The measured shrinkage potentials vary between 2% (alluvial sand) and 65% (peat-clay). The sedge peat and peat-clay are characterised by distinct higher shrinkage potentials compared to the glacial clay and show distinct proportional shrinkage. It has to be pointed out that the soil volume loss partly even exceeds the loss in water volume. The sedge peat does not reach residual or zero shrinkage but shows distinct structural shrinkage at initial desiccation. For the moderately drained site, matric potentials reached up to −60 kPa in summer in 15-cm depth, whilst capillary rise almost prevented desiccation of deeper zones. For the deeply drained site, summer desiccation reached deeper zones as well (matric potential up to −50 kPa in 40-cm depth) due to absent capillary rise. In the range of actually occurring maximum desiccation, the half-bog and peat-clay with high decomposed organic matter are particularly affected by shrinkage with volume decreases of 10-14%, in contrast to the fibred sedge peat with only 4%. When uniquely shrunken substrates will be re-wetted, distinct irreversible shrinkage proportions reaching between 18% and 31% subsequent to drying to a matric potential of −50 kPa and re-saturation were measured. Discussion Particularly, the organic-rich substrates appeared as characteristically sensitive to soil shrinkage. Contrary to mineral substrates, they lack in solid particles, leading, along with high hydraulic stresses due to dominantly finer pores, to intense volume decreases after desiccation. These substrates therefore partly also lack in residual or zero shrinkage, and the soil volume loss can even exceed the water loss due to shrinkage. Accordingly, the alterations of soil properties, e.g. conductivities, are especially pronounced. Conclusions The calc...

show abstract

Section: Discussionmentioning

confidence: 97%

Shrinkage processes of a drained riparian peatland with subsidence morphology

2009

View full text Add to dashboard Cite

show abstract

“…However, using long‐term transient hydrological models requires a thorough understanding of the effect of swelling/shrinking peat soils on water storage capacity (Camporese et al . , ), which is rarely available.…”

Section: Discussionmentioning

confidence: 99%

Quantification of peatland water storage capacity using the water table fluctuation method

Baird

Larocque

Garneau

2017

Hydrological Processes

View full text Add to dashboard Cite

Peat specific yield (SY) is an important parameter involved in many peatland hydrological functions such as flood attenuation, baseflow contribution to rivers, and maintaining groundwater levels in surficial aquifers. However, general knowledge on peatland water storage capacity is still very limited, due in part to the technical difficulties related to in situ measurements. The objectives of this study were to quantify vertical SY variations of water tables in peatlands using the water table fluctuation (WTF) method and to better understand the factors controlling peatland water storage capacity. The method was tested in five ombrotrophic peatlands located in the St. Lawrence Lowlands (southern Québec, Canada). In each peatland, water table wells were installed at three locations (up‐gradient, mid‐gradient, and down‐gradient). Near each well, a 1‐m long peat core (8 cm × 8 cm) was sampled, and subsamples were used to determine SY with standard gravitational drainage method. A larger peat sample (25 cm × 60 cm × 40 cm) was also collected in one peatland to estimate SY using a laboratory drainage method. In all sites, the mean water table depth ranged from 9 to 49 cm below the peat surface, with annual fluctuations varying between 15 and 29 cm for all locations. The WTF method produced similar results to the gravitational drainage experiments, with values ranging between 0.13 and 0.99 for the WTF method and between 0.01 and 0.95 for the gravitational drainage experiments. SY was found to rapidly decrease with depth within 20 cm, independently of the within‐site location and the mean annual water table depth. Dominant factors explaining SY variations were identified using analysis of variance. The most important factor was peatland site, followed by peat depth and seasonality. Variations in storage capacity considering site and seasonality followed regional effective growing degree days and evapotranspiration patterns. This work provides new data on spatial variations of peatland water storage capacity using an easily implemented method that requires only water table measurements and precipitation data.

show abstract

“…The dataset collected at the experimental sites range from soil elevation changes and soil CO 2 efflux to hydrological parameters such as soil moisture content, capillary suction, temperature, etc. The data are published in several works [ Gatti et al , 2002; Fornasiero et al , 2003; Teatini et al , 2004; Gambolati et al , 2005; Camporese et al , 2006a, 2006b; Gambolati et al , 2006; Camporese et al , 2008] and are available from the website http://voss.dmsa.unipd.it.…”

Section: Introductionmentioning

confidence: 99%

Long term peatland subsidence: Experimental study and modeling scenarios in the Venice coastland

et al. 2011

View full text Add to dashboard Cite

[1] Land subsidence in drained cultivated peatlands is responsible for a number of serious environmental concerns and economical problems at both the local and the global scale. In low-lying coastal areas it enhances the risk of flooding, the saltwater contamination of shallow aquifers, and the maintenance costs of the systems that help keep the farmland drained. Since the subsidence is a major consequence of the bio-oxidation of the soil organic fraction in the upper aerated zone, cropped peatlands in temperate and tropic regions are important sources of CO 2 into the atmosphere. A 4-year long experimental study has been performed in a drained peatland located south of the Venice Lagoon, Italy, to help calibrate a land subsidence model developed to predict the expected behavior of the ground surface elevation. Continuous monitoring of the hydrological regime and land displacements shows that the vertical movement of the peat surface consists of the superimposition of daily/seasonal time-scale reversible deformations related to soil moisture, depth to the water table, and temperature fluctuations, and long term irreversible subsidence due to peat oxidation. A novel two-step modeling approach to separate the two contributions from the available observations is presented. First, the elastic component is computed by integrating the peat vertical deformations evaluated by a constitutive relationship describing the porosity variation with the moisture content and pore pressure changes implemented into a variably saturated flow equation-based numerical code. The observed trend is then filtered from the computed reversible displacement and is used to calibrate an empirical relationship relating land subsidence rate to drainage depth and soil temperature. The results show that in recent years the subsidence rate ranged from 3 to 15 mm a −1 . The large variability is due to the different climate conditions underlying the monitoring period, in particular a wet 2002 and a very dry 2003. The model is then used to investigate the effect of human activities and climate change on the expected reduction of the peat thickness. The results suggest that the long term subsidence is mainly controlled by the manner in which the water table is managed in the peatland. For example, the subsidence rate is almost halved if the current 0.5 m mean water table depth is kept at 0.2 m. Conversely, even the extreme warning scenario provided by the IPCC in 2007 do not suggest significant changes on the expected subsidence trend, at least in low lying reclamation areas where the average temperature rise should not be accompanied by a significant reduction of water availability.Citation: Zanello, F., P. Teatini, M. Putti, and G. Gambolati (2011), Long term peatland subsidence: Experimental study and modeling scenarios in the Venice coastland,

show abstract

Hydrological modeling in swelling/shrinking peat soils

Cited by 61 publications

References 32 publications

Shrinkage processes of a drained riparian peatland with subsidence morphology

Shrinkage processes of a drained riparian peatland with subsidence morphology

Quantification of peatland water storage capacity using the water table fluctuation method

Long term peatland subsidence: Experimental study and modeling scenarios in the Venice coastland

Contact Info

Product

Resources

About