Nitrogen fluxes on catchment scale: the influence of hydrological aspects

2005 ◽  
Vol 52 (9) ◽  
pp. 163-173 ◽  
Author(s):  
M. Zessner ◽  
Ch. Schilling ◽  
O. Gabriel ◽  
U. Heinecke

In two catchment areas with altogether eight subcatchments characterising different site-specific situations the interaction between anthropogenic activities (e.g. agriculture, nutrition and waste water management), nitrogen emissions and in stream loads as well as concentrations were studied in detail. Groundwater is the most important pathway for nitrogen inputs into surface waters. Denitrification in the soil/subsurface/groundwater system controls the amount of this input to a high extent. Key factors influencing this process are organic carbon availability, geology, precipitation and groundwater recharge rates as well as residence time in groundwater. The MONERIS emission model is a useful tool to quantify these relationships on (sub-)catchment scale. Areas where concentrations in groundwater (e.g. nitrate) tend to be higher due to little dilution with water and might be problematic in respect to limit values for drinking water, are much less relevant in respect to the loads transported to river systems and receiving seas, than regions with high precipitation. In cases with high water availability mainly high loads transported downstream and finally to the receiving sea are a considerable problem. Within a region mainly areas close to river systems contribute to nitrogen discharges to the river system because of the short residence times of the groundwater from these areas and - related to this - a lower influence of denitrification in the groundwater.

2007 ◽  
Vol 7 (3) ◽  
pp. 103-110
Author(s):  
C. Schilling ◽  
M. Zessner ◽  
A.P. Blaschke ◽  
D. Gutknecht ◽  
H. Kroiss

Two Austrian case study regions within the Danube basin have been selected for detailed investigations of groundwater and surface water quality at the catchment scale. Water balance calculations have been performed using the conceptual continuous time SWAT 2000 model to characterise catchment hydrology and to identify individual runoff components contributing to river discharge. Nitrogen emission calculations have been performed using the empirical emission model MONERIS to relate individual runoff components to specific nitrogen emissions and for the quantification of total nitrogen emissions to surface waters. Calculated total nitrogen emissions to surface waters using the MONERIS model were significantly influenced by hydrological conditions. For both catchments the groundwater could be identified as major emission pathway of nitrogen emissions to the surface waters. Since most of the nitrogen is emitted by groundwater to the surface water, denitrification in groundwater is of considerable importance reducing nitrogen levels in groundwater along the flow path towards the surface water. An approach was adopted for the grid-oriented estimation of diffuse nitrogen emissions based on calculated groundwater residence time distributions. Denitrification in groundwater was considered using a half life time approach. It could be shown that more than 90% of the total diffuse nitrogen emissions were contributed by areas with low groundwater residence times and short distances to the surface water. Thus, managing diffuse nitrogen emissions the location of catchment areas has to be considered as well as hydrological and hydrogeological conditions, which significantly influence denitrification in the groundwater and reduce nitrogen levels in groundwater on the flow path towards the surface water.


2005 ◽  
Vol 51 (3-4) ◽  
pp. 19-29 ◽  
Author(s):  
M. Venohr ◽  
I. Donohue ◽  
S. Fogelberg ◽  
B. Arheimer ◽  
K. Irvine ◽  
...  

The mean annual transfer (loss and retention) of nitrogen in a river system was estimated using a conceptual approach based on water surface area and runoff. Two different approaches for the calculation of water surface area were applied to determine riverine nitrogen retention in four European catchments, ranging between 860–14,000 km2 in area, and differing considerably in the proportion and distribution of surface waters, specific runoff and specific nutrient emissions. The transfer rate was estimated sequentially as either the mean value for the total catchment, on a sub-catchment scale, or considering the distribution of water surface area within a sub-catchment. For the latter measure, nitrogen retention in larger lakes was calculated separately. Nitrogen emissions modelled with MONERIS and HBV-N were used to calculate nitrogen river loads and compare those with observed loads. Inclusion of the proportion of water area within a sub-catchment improved modelled results in catchment with large lakes in sub-catchments, but not where there was a homogenous distribution of surface waters among sub-catchments.


2016 ◽  
Vol 74 (5) ◽  
pp. 1060-1068 ◽  
Author(s):  
Andrea Ackermann ◽  
Judith Mahnkopf ◽  
Claudia Heidecke ◽  
Markus Venohr

We depict recent agricultural nitrogen input and future loads to be expected in 2021 in the German Baltic Sea catchment to assess the feasibility of reaching water quality targets defined by the Marine Strategy Framework Directive (MSFD). We calculate recent and future nitrogen balances from agriculture by applying an interdisciplinary modelling system, also considering the effects of the Nitrate Directive. The nitrogen surpluses are transferred to a nutrient emission model to simulate nitrogen emissions, in-stream retention and resulting riverine loads to the sea until 2021. Finally, we analyse input reduction demands and agri-environmental measures necessary to attain water quality targets of the MSFD. The results are target-oriented mitigation options relevant for implementation, based on regional land use and nitrogen reduction demands. Furthermore, this paper discusses the effects of policies and measures implemented to reduce nitrogen loads.


2017 ◽  
Vol 19 (2) ◽  
pp. 157
Author(s):  
Nunung Puji Nugroho

<p class="JudulABSInd"><strong>ABSTRAK</strong></p><p class="abstrak">Informasi hasil air dari suatu ekosistem sangat penting dalam pengelolaan sumber daya air. Dalam perencanaan kegiatan konservasi sumber daya air, informasi sebaran spasial hasil air diperlukan untuk menentukan prioritas wilayah terkait dengan alokasi anggaran. Hasil air dari suatu ekosistem atau daerah aliran sungai (DAS) dapat diestimasi dengan menggunakan model hidrologi. Penelitian ini bertujuan untuk mendapatkan informasi tentang hasil air, baik besaran maupun sebaran spasialnya, dari daerah tangkapan air (DTA) Danau Rawa Pening. Hasil air dari lokasi penelitian dihitung dengan menggunakan model hasil air pada InVEST (<em>the Integrated Valuation of Ecosystem Services and Tradeoffs</em>), yang didasarkan pada pendekatan neraca air. Hasil perhitungan menunjukkan bahwa volume hasil air di DTA Danau Rawa Pening pada tahun 2015 adalah sekitar 337 juta m<sup>3</sup>. SubDAS Galeh, sebagai subDAS terluas, merupakan penghasil air terbesar (72,4 juta m<sup>3</sup>) diikuti oleh subDAS Sraten (66,8 juta m<sup>3</sup>) dan Parat (62,4 juta m<sup>3</sup>). Secara spasial, hasil air di lokasi kajian mempunyai nilai antara 0 hingga 29.634,19 m<sup>3</sup>/ha. Wilayah hulu dan tengah subDAS Sraten secara umum mempunyai hasil air yang lebih tinggi, sedangkan wilayah danau dan sekitarnya serta hulu subDAS Galeh mempunyai hasil air yang lebih rendah dibandingkan dengan wilayah lainnya. Wilayah dengan hasil air tinggi dapat diprioritaskan dalam kegiatan konservasi sumber daya air untuk mendukung pasokan air ke Danau Rawa Pening.</p><p><strong><em>Kata kunci</em></strong><em>: hasil air, daerah tangkapan air, model InVEST, Danau Rawa Pening</em><em></em></p><p class="judulABS"><strong>ABSTRACT</strong></p><p class="Abstrakeng">Accurate information on water yield from an ecosystem is very important in the management of water resources. In the planning of water resources conservation activities, the information on the spatial distribution of water yield is needed to determine regional priorities related to budget allocations. The water yield from an ecosystem or watershed can be estimated using a hydrological model. This study aimed to obtain information about the water yield, both the magnitude and their spatial distribution, from the catchment areas of Lake Rawa Pening. The water yield from the study area was calculated using the water yield model in InVEST (the Integrated Valuation of Ecosystem Services and Tradeoffs), which based on the water balance approach. The results indicated that the volume of water yield in Lake Rawa Pening for 2015 is approximately 337 million m<sup>3</sup>. Galeh subwatershed, as the largest subwatershed, is the largest water producer (72.4 million m<sup>3</sup>), followed by Sraten subwatershed (66.8 million m<sup>3</sup>) and Parat subwatershed (62.4 million m<sup>3</sup>). Spatially, the water yield at the study site has a value between 0 to 29,634.19 m<sup>3</sup>/ha. Upstream and middle areas of Sraten subwatershed generally have higher water yield, while the lake and its surrounding areas as well as the upstream of Galeh subwatershed have lower water yield compared to other regions. The regions with high water yield can be prioritized in water resource conservation activities to support the supply of water to Lake Rawa Pening.</p><p><strong><em>Keywords</em></strong><em>: water yield, catchment areas, InVEST model, Lake Rawa Pening</em><em></em></p>


2017 ◽  
Vol 68 (8) ◽  
pp. 1744-1748
Author(s):  
Catalina Stoica ◽  
Gabriela Geanina Vasile ◽  
Alina Banciu ◽  
Daniela Niculescu ◽  
Irina Lucaciu ◽  
...  

During the past few decades, the anthropogenic activities induced worldwide changes in the ecological systems, including the aquatic systems. This work analysed the contamination level of groundwater resources from a rural agglomeration (Central-Western part of Prahova County) by biological and physico-chemical approaches. The study was performed during the autumn of 2016 on several sampling sites (four drilling wells, depth higher than 100 m supplying three villages; two wells lower than 10 m depth and one spring). The water quality was evaluated by comparison with the limit values of the drinking water quality legislation (Law no.458/2002) and the Order 621/2014 (applicable to all groundwater bodies of Romania). The results showed that phenols and metals (iron and manganese) exceeded the threshold values in all sampling sites. Moreover, the anthropogenic factors including agriculture, use of fertilizers, manures, animal husbandry led to an increase of the bacterial load, particularly at wells sites.


1989 ◽  
Vol 21 (8-9) ◽  
pp. 1015-1024 ◽  
Author(s):  
C. P. Crockett ◽  
R. W. Crabtree ◽  
I. D. Cluckie

In England and Wales the placing of effluent discharge consents within a statistical framework has led to the development of a new hybrid type of river quality model. Such catchment scale consent models have a stochastic component for the generation of model inputs and a deterministic component to route them through the river system. This paper reviews and compares the existing approaches for consent modelling used by various Water Authorities. A number of possible future developments are suggested including the potential need for a national approach to the review and setting of long term consents.


2021 ◽  
Vol 13 (4) ◽  
pp. 2006
Author(s):  
Ning Ding ◽  
Jingfeng Zhu ◽  
Xiao Li ◽  
Xiangrong Wang

The rapid growth of metropolitan regions is closely associated with high nitrogen (N) flows, which is known as the most important reason for widespread water pollution. It is, therefore, crucial to explore the spatiotemporal patterns of N budgets under intensive human activity. In this study, we estimated the long-term (2000–2015) N budgets by integrating the net anthropogenic nitrogen input (NANI) and the export coefficient model (ECM) in the Yangtze River Delta Urban Agglomeration (YRDUA), a typical metropolitan area with strong human disturbances. The results revealed that the NANI decreased by 10% from 2000 to 2015, while N exports showed a 6% increase. Hotspots for N budgets were found in the northeastern areas, where cropland and construction land were dominant. The linear regression showed a close relationship between the NANI and N export, and about 18% of the NANI was exported into the river system. By revealing the critical sources and drivers of N budgets over time, our work aimed to provide effective information for regional policy on nitrogen management. Future strategies, such as improving the fertilizer efficiency, optimizing the land use pattern, and controlling the population density, are necessary in order to address the environmental challenge concerns of excessive N.


2021 ◽  
Author(s):  
◽  
Tapuwa Marapara

<p>During the last two decades there has been increasing interest in the role of forests and wetlands as flood mitigating tools due to growing concerns regarding the sustainability of many traditional engineering flood defences such as dykes, sea walls and dams. In forests, the role is facilitated by the interaction between trees, soil and water. Specifically trees reduce surface runoff and prevent flooding through increased evapotranspiration and canopy interception and enhance physical and hydraulic properties of soil that are critical for the absorption and retention of flood waters by the soil. It is increasingly realised that the answer to flood mitigation is not a blanket recommendation to “plant trees”. This is because the role of trees varies spatially and temporally as a function of climate, topography, rainfall properties, soil type and condition, catchment scale and geology, among others. For example, where trees are present in wetlands, particularly forested wetlands, the mechanisms by which trees interact with soil and water are similar to that in forests but because of a high water table, the impact of trees may be reduced. Therefore, the mere presence of forests and forested wetlands will not necessarily deliver flood risk management.  The purpose of this study was to explore the effectiveness of trees as flood mitigating tools under various bio-geo climatic factors in forests and forested wetland environments. Three forms of investigation were followed to fulfil this purpose.  A detailed literature review was carried out to assess the role of trees and forests as flood mitigation tools under changing climate, topography, species type, rainfall properties, soil type and condition, catchment scale and geology. A field experiment was carried out to collect data and analyse the effect of trees on soil physical and hydraulic properties that include bulk density, saturated hydraulic conductivity, soil organic carbon, soil moisture content, matric potential and soil moisture retention in a previously forested wetland undergoing restoration in New Zealand. A spatially explicit decision support tool, the Land Use Capability Indicator (LUCI) was then used to determine appropriate areas where intervention can be targeted to optimise the role of trees as flood mitigating tools in previously forested wetlands undergoing restoration.  The detailed review identified a major data gap in the role of trees under hydric conditions (high water table), along with uncertainties on their effectiveness in large catchments (>˜40 km²) and in extreme rainfall events. The field experiment provided the first set of soil hydrology data from an ephemeral wetland in New Zealand showing the benefits of newly established trees in improving hydraulic conductivity of soils. The soil hydrology data is a useful baseline for continuous monitoring of the forested wetlands undergoing restoration. The use of the Land Use Capability Indicator was its first application for the optimisation of flood mitigation in a forested wetland. Its suggested target areas are not necessarily conducive for survival of some tree species, although if suitable species are established, flood risk mitigation could be maximised. Further research on what native species are best for what conditions and in what combinations is recommended, to increase survival in the proposed target areas.</p>


2006 ◽  
Vol 63 (1) ◽  
pp. 176-185 ◽  
Author(s):  
Henriette I Jager

Restoring connectivity is viewed as an important recovery option for fish species adversely affected by river fragmentation. This simulation study quantified the genetic and demographic effects of translocation on metapopulations of white sturgeon (Acipenser transmontanus) inhabiting a series of long (source) and short (sink) river segments. Genetic effects were predictable; upstream translocations increased introgression and downstream translocations had no effect. Demographic results suggest that indiscriminant efforts to reconnect populations may do more harm than good. Simulated river systems with high interspersion of long and short segments and a long segment far upstream tended to benefit most from translocation, but only when narrow screening or downstream passage was also provided below the river segment receiving fish. When combined with narrow screening, upstream translocation to a long segment subsidizing several downstream short segments produced the best results. Downstream passage outperformed narrow screening only when the translocation recipient was a short segment in a river system with low interspersion and no long, upstream river segment. This model-based evaluation of reconnection options has helped to refine ideas about restoring populations in fragmented rivers by predicting which options benefit riverine metapopulations as a whole.


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