Version 2.0.0 with Added support for REALLY large rasters.

Version 2.0.0 Release Notes:

This release sees the addition of nutrient budgets for Nitrogen and Phosphorus. Separate budgets are constructed for particulate, dissolved inorganic and dissolved organic forms. Several interface improvements have also been made to facilitate viewing of scenario attributes, the summary budget and to allow comparison between scenarios. A summary of the changes is below.

We recommend that users familiarise themselves with the changes as they are fully described in the relevant sections of the updated User Guide, as listed in the Document History table at the front of the User Guide.

Technical improvements in addition to the nitrogen and phosphorus budgets:

• The method for applying the MAF hydrology regionalisation has been modified resulting in improved performance particularly in large catchments.
• A transient bedload budget is available as an option that improves prediction of bedload accumulation by representing the transient response to an increase in erosion rates, including the residence time of bedload as moves through each link.
• Hillslope cover factor is now entered using a landuse-based lookup table, to facilitate scenario modelling. In the updated sample dataset, the landuse lookup table is in the ?Data/Tables? folder (this reference is omitted in the User Guide tutorial). Hillslope erosion (USLE) grids can still be used directly as explained in the User Guide.

• The Scenario Manager window provides Copy, Delete and Export scenario buttons. The Run Scenario button is now in the Scenario Editor window. Access to the Contributor View is now via the Scenario Attributes window.
• The differences between two scenarios can be inspected in the Scenario Attribute and Summary Budget windows by loading a second scenario using the "Load to Compare" button in the Scenario Manager.
• The natural ("pre-European") comparison has been removed from each scenario. Natural scenarios can now be created using an option in the New Scenario Wizard; using appropriate datasets for natural conditions including landuse and hillslope vegetation cover.
• Scenario Attributes are now listed in a tree view. Attributes that are unsuitable for use in targeting management measures, because they scale with link length or sub-catchment area (e.g: bank erosion t/y), are listed under "Extras".
• The Summary Budget is presented in a tree view, and can be easily exported for viewing in a spreadsheet.
• Exporting a scenario now provides the link data in a csv file. For viewing in GIS software, the csv file can be joined to the network shapefile using the link ID field. Using csv files avoids the 8 character limit for field names in dbf files, and so the exported field names are now unambiguous.
• It is no longer necessary to "run" regulated flow; this happens automatically when the scenario runs.

• Scenarios that were created in version 1.4.0 onwards can be used in Version 2 for viewing, editing and simulating catchment changes to sediment budgets (i.e. in the same way as for prior versions). The new (improved) hydrology method is not applied to scenarios created in Version 1 when they are opened in Version 2. Editing hillslope erosion in Version 1 scenarios requires use of the landuse lookup table as described above. Nutrient budgets should not be added to Version 1 scenarios or copies thereof, this is due to an error in the (unused) component of the hyrology module in Version 1 that is used to calculate dissolved nutrient supply in Version 2. Building nutrient budgets should only be done using the New Scenario Wizard.

• Windows displaying link data are prone to displaying remnants of previous values. Closing and reopening the program is the best way to solve this problem.
• Directly editing multiple values in the Gully Erosion and Riparian Vegetation windows is sometimes prevented. The workaround is to use the slider bars when editing multiple links.
• Some normal program warning messages are incorrectly displayed as error messages.
• The gauge name field in flow gauge shape files must be in number format, not text.
• Defining a stream network on DEMs with greater than 20 million cells may result in a memory over-run crash. This over-run is caused by a .NET limitation on memory allocation. It is possible to overcome this memory limitation by instructing SedNet to use "Compressed" grids. This is done in the Edit Raster Properties tool by specifying a threshold beyond which SedNet will compress the grids in memory. The default threshold is 30 million cells. If you are experiencing memory issues and your grids have more cells than the specified threshold, go to the same menu item and reduce the value of "Tile Height". CAUTION: The method of compressing grids is not fully tested yet. Grid compression is generally of most importance in the pit filler and stream-define algorithms. Grid compression significantly slows processing; it may take 48 hours or more to run stream define on a DEM above 40 million cells.
• The progress bars for several processing steps do not clearly indicate progress; for large catchment datasets, the program may not respond for some time during normal operation for these steps.
• Grids in .flt format may cause a crash. The work-around is to always use the .asc format when creating and loading grids.