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Asusuo buffer zone area (0.20 ha) receives its inflow water from a 87 ha catchment area. The buffer was constructed by filling in the main outlet ditch from the drainage area upstream as shown in Nieminen et al. (2005a,b). Sampling lines A–E with sampling points for the collection of soil and surface water samples. Concentration of PO 4 –P in soil water at days 1–5 and 10 after the start of the P addition are shown as bar charts.
Source publication
Ilvesniemi, H. 2008. Retention of phosphorus in peatland buffer zones at six forested catchments in southern Finland. Silva Fennica 42(2): 211–231. Our current knowledge of the P retention efficiency of peatland buffer zone areas used to reduce sediment and nutrient leaching from forestry areas is insufficient. Especially the role of P sorption by...
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Peatland buffer areas are important means in reducing sediment and nutrient loading from discharge waters in a variety of
landscapes; however, use of natural mires as buffer areas may induce unwanted changes in the plant species composition. Vegetation
composition dynamics were studied at one rewetted peatland and two natural peatlands used as buff...
Citations
... Enhanced water protection with wider buffer zones [40,[75][76][77][78][79][80] or the favoring of continuous cover forestry [81][82][83] can be applied to future forest management only and, therefore, separating background export hotspots from management-induced hotspots ( Figure 10) is essential. Cost-efficient water protection calls for targeting the investments to areas where the background export is high or will become high as a result of forest management. ...
The implementation of the Water Framework Directive (WFD) aimed to reduce nutrient export from catchments to water courses. Forest operations cause diffuse loading, which challenges the efficient targeting of water protection measures. We formed 100 equally probable clear-cut scenarios, to investigate how the location of the clear-cuts influenced the total nitrogen (TN) and phosphorous (TP) export on different scales. The nutrient export was calculated by using a distributed nutrient export model (NutSpaFHy). The clear-cut-induced excess TN and TP exports varied by 4.2%–5.5% and 5.0%–6.5%, respectively, between the clear-cut scenarios. We analyzed how the sub-catchment characteristics regulated the background export. The results also suggested that there was no single sub-catchment feature, which explained the variation in the TN and TP exports. There were clear differences in the background export and in the clear-cut-induced export between the sub-catchments. We also found that only 5% of the forest area could contribute up to half of the total nutrient export. Based on our results, we presented a conceptual planning framework, which applied the model results to finding areas where the nutrient export was high. Application of this information could improve the overall effectiveness of the water protection measures used in forestry.
... A common idea behind various water protection structures is to decrease the water velocity, so that SS can be sedimented and nutrients can be absorbed before reaching downstream lakes and rivers. The most effective methods have proved to be overland flow fields (Väänänen et al., 2008;Vikman et al., 2010), PRCs (Marttila and Kløve, 2010b), and breaks in ditch cleaning (Haahti et al., 2017). ...
... The purpose of this study was to develop spatial analysis to propose suitable locations for overland flow fields and uncleaned ditch sections within a forested catchment. Overland flow fields are often placed just before stream water discharging from forest catchments reaches larger watercourses, but practically they can be placed anywhere within a catchment where water protection is needed and topography is suitable (Väänänen et al., 2008;Vikman et al., 2010). Leaving breaks in ditch cleaning is a common and cost-efficient method to decrease flow velocity, enhance sediment deposition from runoff water (Haahti et al., 2017), and mitigate biodiversity loss in DNM (Vaikre et al., 2020). ...
... Overland flow fields can be placed between load sources and watercourses, where topography is suitable. Good purification results for reduced contaminants have been measured from runoff water (Väänänen et al., 2008;Vikman et al., 2010), but the efficiency is significantly lowered during peak flow periods (Vuori and Joensuu, 1996;Liljaniemi et al., 2003). ...
Peatland forest management is an important source of human-induced additional nitrogen, phosphorus, and organic carbon loads to surface waters in Finland. Ditch network maintenance (DNM) is typically used to ensure sufficient soil drainage for profitable timber production on peatland sites, but nutrient mobilization, particularly of phosphorus, and suspended sediment loads from ditches can cause harmful ecological effects on the quality of water courses. Various water protection structures have been developed to capture the loads released after treatments and to decrease the management impacts in forestry. Overland flow fields are efficient mechanisms for water purification, but they are rarely used in practice due to difficulties in finding suitable locations. In addition, leaving breaks between cleaned ditch sections is recommended wherever possible, as uncleaned sections decrease flow velocity and enhance sediment deposition from runoff water. To plan the most adequate protection methods in DNM, new GIS-based tools are needed to propose e.g. appropriate locations for water protection structures. We developed a spatial analysis to suggest locations for overland flow fields and uncleaned ditch sections within the catchment of lake Kovesjärvi (Parkano, Western Finland). Airborne lidar data consisting of 5 pulses m−2 enabled detailed terrain analysis and finding strictly specified terrain properties that satisfied the conditions of the water protection structures. Half of the field-reviewed overland flow fields were evaluated as good suggestions by forest management professionals and researchers. The model for uncleaned ditch sections worked well on the relatively flat study area, as 77% of the field-reviewed suggestions were rated good by expert opinions. Overall, the approach was evaluated to be useful in peatland forest management. Model parameters can be modified for various topographies, but more studies are needed prior to wider use of the model.
... The goal of the sedimentation ponds is to improve water quality by allowing suspended sediments and sediment-bound contaminants to settle within the pond. Overflow fields and constructed wetlands are typically employed before the runoff can reach the water bodies (e.g., Joensuu, 2002;Väänänen et al., 2008). Sedimentation-based and flow-control water protection methods can retain coarse-textured mineral soil particles from the runoff waters or prevent ditch erosion in the first place (Liljaniemi et al., 2003;Nieminen et al., 2005a;Eskelinen et al., 2015). ...
Water quality is significantly affected by the forest logging activities that are carried out in drained peatlands, which causes a notable enhancement in sediment loading and nutrient export to water bodies. Furthermore, the seasonal fluctuations in nutrient concentrations in the runoff further underscore the need for efficient water protection tools in peatland forestry. To address these issues, biochar-based adsorption methods can potentially offer an effective alternative for water protection in peatland forestry. The current thesis investigates the potential for adsorption-based nutrient recovery from clear-cut peatland runoff water using Norway spruce and Silver birch biochars. In particular, the aim is to i) study the adsorption characteristics in relation to biochar properties and nutrient compounds in runoff waters in a small-scale laboratory experiment (Paper I); ii) investigate the adsorption characteristics of nitrogen (N) compounds from runoff water in a meso-scale laboratory experiment that utilises biochar reactors (Paper II); and iii) investigate the dynamics of biochar adsorption and desorption under fluctuating total nitrogen (TN) concentrations in runoff water (Paper III). Biochar made from birch and spruce were shown to efficiently adsorb N compounds from the water. Across all experiments, the TN content declined significantly, irrespective of the scale, or whether the runoff volume ranged from litres (I and III) to hundreds of litres (II). Furthermore, the TN content at the beginning of the experiment declined at the fastest rate. The results indicate that cases of relatively low adsorption capacity were attributed to the low initial TN concentrations in the water. In addition, TN adsorption occurs above a threshold concentration in natural runoff water. The spruce did not adsorb TN when the concentrations in the runoff water fell below 0.4 mg L-1. In this thesis, biochar emerges as a compelling water protection solution, particularly in regions where clear-cut peatlands release substantial quantities of nutrients.
... The goal of the sedimentation ponds is to improve water quality by allowing suspended sediments and sediment-bound contaminants to settle within the pond. Overflow fields and constructed wetlands are typically employed before the runoff can reach the water bodies (e.g., Joensuu, 2002;Väänänen et al., 2008). Sedimentation-based and flow-control water protection methods can retain coarse-textured mineral soil particles from the runoff waters or prevent ditch erosion in the first place (Liljaniemi et al., 2003;Nieminen et al., 2005a;Eskelinen et al., 2015). ...
Water quality is significantly affected by the forest logging activities that are carried out in drained peatlands, which causes a notable enhancement in sediment loading and nutrient export to water bodies. Furthermore, the seasonal fluctuations in nutrient concentrations in the runoff further underscore the need for efficient water protection tools in peatland forestry. To address these issues, biochar-based adsorption methods can potentially offer an effective alternative for water protection in peatland forestry. The current thesis investigates the potential for adsorption-based nutrient recovery from clear-cut peatland runoff water using Norway spruce and Silver birch biochars. In particular, the aim is to i) study the adsorption characteristics in relation to biochar properties and nutrient compounds in runoff waters in a small-scale laboratory experiment (Paper I); ii) investigate the adsorption characteristics of nitrogen (N) compounds from runoff water in a meso-scale laboratory experiment that utilises biochar reactors (Paper II); and iii) investigate the dynamics of biochar adsorption and desorption under fluctuating total nitrogen (TN) concentrations in runoff water (Paper III). Biochar made from birch and spruce were shown to efficiently adsorb N compounds from the water. Across all experiments, the TN content declined significantly, irrespective of the scale, or whether the runoff volume ranged from litres (I and III) to hundreds of litres (II). Furthermore, the TN content at the beginning of the experiment declined at the fastest rate. The results indicate that cases of relatively low adsorption capacity were attributed to the low initial TN concentrations in the water. In addition, TN adsorption occurs above a threshold concentration in natural runoff water. The spruce did not adsorb TN when the concentrations in the runoff water fell below 0.4 mg L-1. In this thesis, biochar emerges as a compelling water protection solution, particularly in regions where clear-cut peatlands release substantial quantities of nutrients.
... Nutrient and sediment export from DNM operations can be mitigated by avoiding unnecessary ditch cleaning or by adapting the minimum required ditch depth according to climatic conditions, stand volume, peat properties, and ditch spacing ). In addition, nutrient and sediments loads can be reduced by constructing water protection structures, such as sedimentation ponds, peak runoff controls, buffer zones, and overland flow fields, and by leaving breaks in ditch cleaning operations (Väänänen et al. 2008;Marttila and Kløve 2010;Vikman et al. 2010;Finér et al. 2018;Haahti et al. 2018). ...
In Finland, peatland forests are significant for wood supply, although simultaneously, they are also important for biodiversity, carbon sequestration, water conservation, and recreation. In the 1960s and 1970s, peatland forests in Finland were extensively drained to increase tree growth and fulfil the needs of the forest sector. However, this extensive drainage has negatively impacted on the biodiversity of peatland ecosystems, and substantially increased nutrient and sediment emissions to lakes and rivers resulting in eutrophication, turbidity, and brownification of these water bodies. This dissertation presents a number of approaches to move peatland forest management in a more environmentally sound direction, which may increase the general acceptability of peatland forestry. Airborne LiDAR (Light detection and ranging, i.e., laser scanning) derived 3D point cloud provides useful data, for example, to estimate forest biomass, to identify low-productive peatland forests, to model overland water flows, and to identify wet areas. The strength of airborne LiDAR is the ability of laser pulses to pass through tree canopies and obtain accurate observations from the ground level. The information derived from airborne LiDAR can enhance the planning of peatland forest management, as much of the planning can be done remotely, and supplementary field work can be implemented in areas of strategic need. This study presented the novel idea of applying local binary patterns for the prediction of terrain trafficability, which should be considered in further studies and practice. The moisture index derived from the local neighborhood can reveal the small-scale variations in terrain moisture. This study also presented the novel idea to create spatial models to identify suitable locations for water protection structures, which may help forest managers to plan water protection of ditch network maintenance or peatland restoration operations. Overall, the utilization of airborne LiDAR-derived information for the development of peatland forestry practices shows great potential.
... One of the widely recommended methods to protect water courses from the negative impacts of forest harvesting activities is to divert the runoff through a natural or restored buffer area before it enters the water courses (Silvan et al. 2004a;Nieminen et al. 2005;Väänänen et al. 2008;Vikman et al. 2010). However, in Ireland and the UK, the establishment of riparian buffer areas was not considered during the afforestation of the majority of upland blanket peat catchments and trees were planted up to the edges of streams (Ryder et al. 2011). ...
... Additionally, even if established, they may not be very effective in retaining nutrients as more than 70% of the nutrients are released during storm events from harvested blanket peat sites (Rodgers et al. 2010). During storm events, the hydraulic loading entering the buffer areas is generally very high and nutrient retention efficiency of buffer areas is very low (Silvan et al. 2005;Väänänen et al. 2008;Vikman et al. 2010;Asam et al. 2012). O'Driscoll et al. (2014b) reported only 18% retention of P by buffer area created in a blanket peatland forest in the west of Ireland. ...
Forest harvesting activities on peatlands have long been associated with nutrient leaching and deterioration of downstream water quality. This study aims to assess the effect of grass seeding practice on harvested blanket peatlands to immobilize N and reduce its export to water courses. First, a plot-scale field experiment was conducted by seeding with two grass species (Holcus lanatus and Agrostis capillaris) to study the N uptake potential from a harvested area. Secondly, a simulated rainfall experiment was conducted to study the effect of these grasses on reducing N leaching from surface peat using laboratory flume approach. In the end, the role of seeded grasses in removing N from nutrient-rich throughflow water was assessed using simulated overland flow experiment. The results showed that the seeded grasses had the potential to uptake over 30 kg ha⁻¹ of N in the first year after seeding on harvested peatlands, whereas it takes over 2.5 years to establish the same level of N uptake by natural re-vegetation (non-grassed). In the simulated rainfall experiment, the inorganic N (NH4⁺-N and NO3⁻-N) leaching in surface runoff from grassed flumes was 72% lower (453 mg m⁻²) than non-grassed flumes (1643 mg m⁻²). In the simulated overland flow experiment, the N retention by grassed flumes was significantly higher (98%) as compared to non-grassed flumes (70%) in the simulated overland flow experiment. Comparatively higher concentrations of NH4⁺-N and NO3⁻-N in soil porewaters of non-grassed flumes suggest that this N retention by non-grassed flumes is less sustainable and is likely to be leached in runoff in subsequent flow events. The results from all three experiments in this study suggest that seeded grasses are a major sink of N on harvested blanket peatland forests. Immobilization of N onsite using the grass seeding and mini-buffer practice could be an efficient and a feasible mean of reducing N export from harvested blanket peatland forests in order to protect the sensitive water courses. However, the sustainability of retention and immobilization of N by grasses needs to be studied further in long-term field-scale experiments on multiple peatland sites.
... In previous studies, no significant correlation was observed between peatland percentages and leaching of P (Kortelainen and Saukkonen, 1998;Mattsson et al., 2003;Kortelainen et al., 2006). Our results indicated that P is in low supply and tightly retained in catchments with pristine peat soil (see Fig. 6b), as previously suggested by Väänänen et al. (2008). ...
More reliable assessments of nutrient export to surface waters and the Baltic Sea are required to achieve good ecological status of all water bodies. Previous nutrient export estimates have recently been questioned since they did not include the long-term impacts of drainage for forestry. We made new estimates of the total nitrogen (N), total phosphorus (P) and total organic carbon (TOC) export from forests to surface waters at different spatial scales in Finland. This was done by formulating statistical equations between streamwater concentrations and climate, soil, forest management and runoff variables and spatial data on catchment characteristics. The equations were based on a large, long-term runoff and streamwater quality dataset, which was collected from 28 pristine and 61 managed boreal forest catchments located around Finland. We found that the concentrations increased with temperature sum (TS), i.e. from north to south. Nitrogen, P and TOC concentrations increased with the proportion of drained areas in the catchment; those of N and TOC also increased with the proportion of peatlands. In contrast, with the increasing concentrations of N and TOC with time, P concentrations showed a decreasing trend over the last few decades. According to our estimates, altogether 47,300 Mg of N, 1780 Mg of P and 1814 Gg of TOC is transported from forest areas to surface waters in Finland. Forest management contributes 17% of the N export, 35% of the P export and 12% of the TOC export. Our new forest management export estimates for N and P are more than two times higher than the old estimates used by the environment authorities. The differences may be explained by the long-term impact of forest drainage. The spatial results indicate that peatland forests are hotspots for N, P and TOC export, especially in the river basins draining to the Gulf of Bothnia.
... Also, OLF studies have indicated that the key factor explaining the nutrient and suspended solids retention efficiency is the size of the buffer relative to the size of the whole upstream catchment area. Studies of Väänänen et al. (2008) and Vikman et al. (2010) showed that retention of nutrient was highest in large catchment areas compared to small ones (at least >1% of the catchment area) (Table 8), furthermore the length of the buffer zone seem to be important, which is probably due to the fact that the formation of continuous flow channels across buffer area is lower for long buffers than short buffers (Nieminen et al., 2014). Also, the dense vegetation has importance in nutrient retention, not only through nutrient accumulation in plant biomass but also because of dense vegetation cover forms a hydraulically rough surface and slows down the water flow velocity through the buffer area (Nieminen et al., 2014). ...
The aim of this document is to critically analyse and document hydro-meteorological hazards, their negative consequences and good practice examples of NBS to manage the associated risks in OPERANDUM OALs. The outcomes of this deliverable serve as a foundation for the various tasks in other WPs of OPERANDUM. For instance, the evidence summarised from Section 3 to Section 7, feeds into WP2 to WP7 for design/co-design and implementation of NBS for flooding, droughts, salt intrusion, landslides, coastal erosion and storm surge, nutrients and sediment loading across OPERANDUM OALs. Overall, the reviewed documents showed that hydro-meteorological risks occur more regularly with a strong increase in intensity to cause significant loss of life and economic damage in OPERANDUM OAL countries and these hazards are projected to increase in severity and duration under future climate change scenarios. In response to this, in OPERANDUM OALs, different types of NBS such as green, blue and hybrid approaches were used and are under implementation
... One example of a commonly used BMP is riparian vegetated buffer. These have seen considerable work surrounding their efficiency for water filtration (Vidon and Hill, 2004;Väänänen et al., 2008;Stutter et al., 2009;Roberts et al., 2012;Stutter et al., 2012a) and habitat provision (Gregory et al., 1991;Kauffman et al., 1997;Bennet and Mulongoy, 2006;Broadmeadow et al., 2011), yet from a diffuse P mitigation perspective, nutrient saturated vegetated buffers can also act as a source of P to waterbodies if not managed correctly in the medium-long term (Stutter et al., 2009;Prosser et al., 2020). Despite this, there is evidence that the multiple benefits provided by some on-farm mitigation measures, riparian vegetated buffers in particular, are a net positive for ecological integrity (Cole et al., 2020), and therefore, potentially beneficial for water quality in the longer term. ...
This thesis investigates the risks posed by organic phosphorus (P) from agriculture to river and stream chemical water quality and the ecology. Organic P compounds have received limited attention in past research, due to the agronomic focus on inorganic P and the analytical challenges of quantifying organic P in environmental matrices. Through laboratory and field experiments, this thesis aimed to: (i) characterise organic P within fresh and stored livestock slurry; (ii) quantify organic P export within overland flow and leachate from grasslands, including following livestock slurry application; and (iii) determine the benthic microbial responses to organic P compounds in rivers and streams. Finally, a coupled terrestrial-aquatic modelling approach was developed to quantify the impact of diffuse agricultural P mitigation measures on river water quality.
The organic P pool in fresh livestock slurry was substantial and dominated by monoesters, including glycerophosphates, other labile monoesters (e.g. ATP) and inositol-6-phosphates. Storage drove significant changes in the chemical and physical fractionation of P within slurry. Organic P was observed in overland flow and leachate from grassland soil. Significant increases in organic P concentrations within leachate followed slurry application, predominantly in the form of glycerophosphates and inositol-6-phosphates. Within streams, heterotrophic responses to glycerophosphates and inositol-6-phosphate were observed, although these varied depending on background stream P concentrations. However, under certain stream conditions, inhibitory effects of organic P on the autotrophic community were observed. Modelling the efficacy of agricultural P mitigation suggested a best-case scenario in which annual river total P loads decreased by 7.5%, yet this increased to 19.4-25.1% when wastewater effluent was addressed alongside agricultural sources of P. The outcomes of this thesis present an opportunity to develop an organic P focus to the P transfer continuum, alongside highlighting a range of future research priorities related to organic P in the environment.
... Several water protection measures are used in peatland forests, including overland flow fields, sedimentation ponds, peak runoff control dams, sedimentation pits, and ditch breaks (Joensuu et al. 1999;Liljaniemi et al. 2003;Marttila et al. 2010;Nieminen et al. 2005Nieminen et al. , 2018aVäänänen et al. 2008;Vikman et al. 2010;Hynninen et al. 2011;Haahti et al. 2018). Overland flow fields are pristine or restored mires over which drainage waters from drained peatlands are conducted (Nieminen et al. 2005;Päivänen and Hånell 2012). ...
... Overland flow fields are pristine or restored mires over which drainage waters from drained peatlands are conducted (Nieminen et al. 2005;Päivänen and Hånell 2012). They efficiently reduce both sediment and dissolved nutrient transport, particularly if the size of the overland flow field is at least 0.5%-1% of the upstream catchment area and the sediment and nutrient loadings entering the overland flow field are high (Nieminen et al. 2005;Sallantaus et al. 1998;Vikman et al. 2010;Väänänen et al. 2008). Overland flow fields are currently considered the most efficient water protection structures in forested catchments (Nieminen et al. 2018a). ...
... Thus, we assume no increase in particulate phosphorus due to final felling, and based on Nieminen (2003), we assume that approximately 77% of the dissolved phosphorus load from final felling is in inorganic form. Based on the average retention calculated by Väänänen et al. (2008) and Silvan et al. (2005), overland flow fields are assumed to retain approximately 77% of this dissolved inorganic phosphorus load. The remaining 23% of the dissolved phosphorus load from final felling is in organic form, and we assume that the overland flow fields are unable to retain it (Nieminen et al. 2015). ...
Ditch network maintenance promotes forest growth in drained peatland forests but increases nutrient and sediment loads, which are detrimental to water quality. Society needs to balance the harvest revenue from improved forest growth against deteriorating water quality. We examine socially optimal even-aged forest management in drained peatlands when harvesting and ditch network maintenance cause nutrient and sediment loading. The means to reduce loading include establishing overland flow fields and abstaining from ditch network maintenance. We characterize this choice analytically in a rotation framework and examine, in a numerical model, the key factors affecting the choice of forest management and water protection measures. We choose a drained peatland forest site located in northeastern Finland in the vicinity of ecologically vulnerable forest headwater streams. On the given drained forest site, we find a set of parameters under which implementing ditch network maintenance is privately but not socially optimal.
