15. Objectives -
• Total number of septic tanks in each water
body catchment.
• Percentage of household on septic tanks.
• Number of people using septic tanks.
• Priority catchment works
• Calculating loads (i.e. N, P) in each water
body catchment.
24. • Image classification
• A supervised classification was carried out using
Maximum Likelihood algorithms.
• ML failed to classify some of the wetland species
e.g. saltmarsh (overall accuracy is less than 60%).
Although I’m focusing on the River Almond catchment here, this analysis was carried out for the whole of Scotland in one go.
Analysis conducted with ESRIs Network Analyst extension to ArcGIS.
Start with just the river network – could be any network, e.g. the OS Water Network.
Although I’m focusing on the River Almond catchment here, this analysis was carried out for the whole of Scotland in one go.
Analysis conducted with ESRIs Network Analyst extension to ArcGIS.
Start with just the river network – could be any network, e.g. the OS Water Network.
Add obstacles to fish migration – green triangles are natural barriers, e.g. water falls, red circles are impassable artificial barriers. Other symbols are partially passable obstacles.
The tools in Network Analyst allow the identification of all the rivers upstream of each obstacle (coloured sections of river network).
This analysis excluded the headwaters of the network (catchment area < 1.5km2), hence the fine blue head water streams have not been highlighted.
The final stage of this analysis is the classification of each sub-catchment based on the length of river excluded / highlighted on the previous slide.
These results can help prioritise where to spend resources by targeting which barriers to remove to provide the most habitat & in what order.
Trying to put this type of analysis into a flooding context, you could have the points representing the location of culverts & repeat the analysis to calculate the length (or wetted area) of river upstream of each culvert.
The form attribute allows the identification of the type of line in the water network – from a cartographic perspective, the loch centre lines can be easily removed via a definition query.
The examples shown have used a 1:50,000 river network, but the same processes could be run on a more detailed river network such as the OS Water Networks layer. Here we see the significant additional features captured in the water networks layer compared with the 1:50k network (blue).
Catchment boundaries – can be used to generate approximations of flow.
Started with the water network & DTM.
Used these with the tools in the spatial analyst extension of ArcGIS to generate the catchment boundaries.
See how the old boundaries (grey) compare with the new boundaries (red).
