Water quality

We will measure soil water in peat and streams at the flow weirs to determine basic quality indicators such as pH, DOC, POC. The peat and stream water colour will be monitored and will reveal linkages between management, vegetation, weather conditions and observed export of carbon via DOC and POC. We are using rhizon samplers to collect peat soil water (see Clark et al., 2012) and sample stream water at the flow weirs (which are located at the sub-catchment outlets).

Importantly, we did not find any difference in peat DOC between burnt mown and uncut plots. In fact, DOC declined over time, which could be linked partly to an increase in both pH and temperature. However, we did find increase DOC in mown catchments over time during the post-management period, clearly linking to carbon released during decomposition from the brash layer.


Different water coloration reflecting different export rates of DOC and POC



DOC plots

Water sample DOC values (ppm or mg per L) across the three sites before vs. after treatment started (March 2013) for monitoring PLOTS




POC per ha time series

Monthly POC export in stream flow based on flow weir samples (per ha) at all three sites during pre-treatment and post treatment periods (ie after mowing and burning early in 2013) - missing values due to drought (ie no flow) or pending analyses. There was no significant difference between burnt and mown catchments, but between sites.



Fire causes air pollution but can also impact on water quality



DOC slopes

Water sample DOC values (ppm or mg per L) across the three sites before vs. after treatment started (March 2013) for SLOPES




DOC per ha time series

Monthly DOC export in stream flow based on flow weir samples (per ha) at all three sites during pre-treatment and post treatment periods (ie after mowing and burning early in 2013) - missing values due to drought (ie no flow) or pending analysesThere was no significant difference between burnt and mown catchments, but between sites.


However, many other plant and soil processes impact on stream water quality



DOC stream flow

Water sample DOC values (ppm or mg per L) across the three sites  before vs. after treatment started (March 2013) for STREAM FLOW


Table outlining the annual POC and DOC carbon  export from each site (average of burnt & mown as there was no difference) for either the overall average (AVG) or the pre- and post-management periods:


All AVG   1.9 25.3
PRE AVG   7.2 44.5
(g m-2 yr-1) Nidd 9.6 48.8
Moss 4.7 45.3
Whit 7.2 39.4
     
POST AVG   1.2 22.9
(g m-2 yr-1) Nidd 1.5 17.1
Moss 0.8 30.5
Whit 1.4 21.2


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