Effect of land use and moisture on phosphorus forms in upland stream beds in South Otago, New Zealand

2009 ◽  
Vol 60 (7) ◽  
pp. 619 ◽  
Author(s):  
Richard W. McDowell

Land use can influence stream sediment composition and water quality, whereas moisture status affects sediment phosphorus (P) bioavailability to algae. Declining upland surface-water quality in South Otago, New Zealand, may reflect land-use changes from sheep- to dairy-farming. I sampled sediment (0–20 cm) from streams draining 12 dairy- and 12 sheep-farmed catchments in spring (wet) and autumn (dry). 31P nuclear magnetic resonance (NMR) spectroscopy and the EDTA-fractionation scheme were used to determine different P forms and infer P bioavailability. Significantly more P was present in the sediment of streams draining dairy- than sheep-farmed catchments. Total P did not differ with the moisture regime; however, changes occurred in the following P fractions: acid-soluble organic P, NaOH-P, CaCO3≈P, Fe(OOH)≈P and residual organic P. Extraction for 31P NMR analysis removed 78–85% of sediment total P and isolated five P classes. More bioavailable P such as orthophosphate (23–40% of P extracted) and diesters (2–6% of P extracted) was present in dry than in wet sediments, and in sediments draining dairy streams than in those from sheep-farmed catchments. This indicates substantial reserves of bioavailable P in sediment from these catchments, especially from dairy-farmed catchments, sustaining in-stream P concentrations for many years even without additional P input from land.

Author(s):  
R. Scott Winton ◽  
Cristian R. Teodoru ◽  
Elisa Calamita ◽  
Fritz Kleinschroth ◽  
Kawawa Banda ◽  
...  

Hydropower dams along with urban and agricultural land-use changes are altering surface water quality in the Zambezi River Basin, Zambia. Field data reveal local impacts and point to monitoring needs for safeguarding water resources under pressure.


2021 ◽  
Vol 776 ◽  
pp. 146034
Author(s):  
Cira Buonocore ◽  
Juan Jesús Gomiz Pascual ◽  
María Luisa Pérez Cayeiro ◽  
Rafael Mañanes Salinas ◽  
Miguel Bruno Mejías

2021 ◽  
Vol 933 (1) ◽  
pp. 012010
Author(s):  
S A Nurhayati ◽  
M Marselina ◽  
A Sabar

Abstract Increasing population growth is one of the impacts of the growth of a city or district in an area. This also happened in the Cimahi watershed area. As the population grows, so does the need for land which increases the land-use change in the Cimahi watershed. Land-use changes will affect the surrounding environment and one of them is the river, especially river water quality. As a watershed area, there is one main river that is the source of life as well as the Cimahi watershed, whose main river is the Cimahi River. The purpose of this study was calculated the relationship between land-use change in the Cimahi watershed and the water quality parameters of the Cimahi River. The correlation between the two was calculated using Pearson correlation. Water quality parameters can be seen based on BOD and DO values. BOD and DO values are the opposite because good water quality has high DO values and low BOD values. The correlation between land-use change and BOD was 0.328 is in the area of settlements area. In contrast, to DO values, an increase in settlements/industrial zones will further reduce DO values so that both have a negative correlation, which is indicated by a value of -0,535. The correlation between settlements with pH and temperature values is 0.664 and 0.812. While the correlation between settlements with TSS and TDS values are 0.333 and 0.529, respectively. In this study, it can be seen that there is a relationship between the decline in water quality and changes in land use.


Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 724 ◽  
Author(s):  
Pankaj Kumar ◽  
Rajarshi Dasgupta ◽  
Brian Johnson ◽  
Chitresh Saraswat ◽  
Mrittika Basu ◽  
...  

Rapid changes in land use and land cover pattern have exerted an irreversible change on different natural resources, and water resources in particular, throughout the world. Khambhat City, located in the Western coastal plain of India, is witnessing a rapid expansion of human settlements, as well as agricultural and industrial activities. This development has led to a massive increase in groundwater use (the only source of potable water in the area), brought about significant changes to land management practices (e.g., increased fertilizer use), and resulted in much greater amounts of household and industrial waste. To better understand the impacts of this development on the local groundwater, this study investigated the relationship between groundwater quality change and land use change over the 2001–2011 period; a time during which rapid development occurred. Water quality measurements from 66 groundwater sampling wells were analyzed for the years 2001 and 2011, and two water quality indicators (NO3− and Cl− concentration) were mapped and correlated against the changes in land use. Our results indicated that the groundwater quality has deteriorated, with both nitrate (NO3−) and chloride (Cl−) levels being elevated significantly. Contour maps of NO3− and Cl− were compared with the land use maps for 2001 and 2011, respectively, to identify the impact of land use changes on water quality. Zonal statistics suggested that conversion from barren land to agricultural land had the most significant negative impact on water quality, demonstrating a positive correlation with accelerated levels of both NO3− and Cl−. The amount of influence of the different land use categories on NO3− increase was, in order, agriculture > bare land > lake > marshland > built-up > river. Whereas, for higher concentration of Cl− in the groundwater, the order of influence of the different land use categories was marshland > built-up > agriculture > bare land > lake > river. This study will help policy planners and decision makers to understand the trend of groundwater development and hence to take timely mitigation measures for its sustainable management.


2020 ◽  
Vol 12 (14) ◽  
pp. 5500 ◽  
Author(s):  
Yu Song ◽  
Xiaodong Song ◽  
Guofan Shao

Intense human activities and drastic land use changes in rapidly urbanized areas may cause serious water quality degradation. In this study, we explored the effects of land use on water quality from a landscape perspective. We took a rapidly urbanized area in Hangzhou City, China, as a case study, and collected stream water quality data and algae biomass in a field campaign. The results showed that built-up lands had negative effects on water quality and were the primary cause of stream water pollution. The concentration of total phosphorus significantly correlated with the areas of residential, industrial, road, and urban greenspace, and the concentration of chlorophyll a also significantly correlated with the areas of these land uses, except residential land. At a landscape level, the correlation analysis showed that the landscape indices, e.g., dominance, shape complexity, fragmentation, aggregation, and diversity, all had significant correlations with water quality parameters. From the perspective of land use, the redundancy analysis results showed that the percentages of variation in water quality explained by the built-up, forest and wetland, cropland, and bareland decreased in turn. The spatial composition of the built-up lands was the main factor causing stream water pollution, while the shape complexities of the forest and wetland patches were negatively correlated with stream water pollution.


Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 189 ◽  
Author(s):  
Matjaž Glavan ◽  
Sara Bele ◽  
Miha Curk ◽  
Marina Pintar

Intensive agriculture causes nutrient leaching and accelerates erosion processes, which threatens the good quality status of surface waters, as proposed by the European Union (EU) Water Framework Directive. The purpose of this study was to define the impact of two alternative agricultural land-use change scenarios defined in a Municipal Spatial Plan on surface water quality by using the Agricultural Policy/Environmental eXtender (APEX) model. As experimental area, we chose a small Kožbanjšček stream catchment (1464 ha) situated in the Goriška Brda region in Slovenia. The area, due to favorable conditions for vineyards, is facing increasing deforestation. The change of 66.3 ha of forests to vineyards would increase the sediment, nitrate, and phosphorus loads in the stream by 24.8%, 17.1%, and 10.7%, respectively. With the implementation of vegetative buffer strips as a mitigation measure of the current situation, we could reduce the sediment, nitrate, and phosphorus loads by 17.9%, 11.1%, and 3.1%, respectively, while a combination of the two land-use change scenarios would result in a slight increase of the above-mentioned loads, corresponding to 0.61%, 2.1%, and 6.6%, respectively, compared to the baseline situation. The results confirm that, as we can increase pollution levels with deforestation, we can also reduce water pollution by choosing proper types of land management measures.


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