Using New Swedish Digital Elevation Model for hydromorphological modelling. Mats Svensson SWAM

Transcription

1 Using New Swedish Digital Elevation Model for hydromorphological modelling Mats Svensson SWAM

2 borrowed feathers Slides and info compiled from several sources and persons; Lantmäteriet, Johan Kling SWAM, Håkan Olsson SMHI, Linus Johnsson and Janos Steiner Lst Kalmar, Johan Björklind Lst Stockholm Presentationsnamn Namn 2

3 What is New Swedish Digital Elevation Model? Based on a recommendation made by the Climate and Vulnerability Commission in their report (SOU 2007:60), the Government has commissioned Lantmäteriet to produce a New National Elevation Model (In Swedish: Ny Nationell Höjdmodell) with high and known accuracy. Since 2009, Lantmäteriet is carrying out airborne laser scanning (LiDAR) in accordance with a plan embracing the requirements connected to climate change and other environmental issues. The aim is to produce a new Digital Elevation Model (DEM) in which the standard error is better than 0,5 m for grid points in a 2 metre grid. 3

4 It is like getting new glasses! Presentationsnamn Namn 4

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6 Swedish National Network för NNH2+ SWAM initiated a national network for people working with NNH2+ Improve dissemination of applications for analysis of NBH2+ data Stimulate collaboration Share resources, data sets, tips&tricks Not reinventing the wheel Work as a unified user community towards Lantmäteriet, to get adapted sets of data, suiting watershed areas Think outside the box Presentationsnamn Namn 6

7 New possibilites New planning and analysis perspectives Better climate adaptations on regional level Considerably better climate adaptations on local level Improved flooding scenario analysis Better planning of WFD measures Presentationsnamn Namn 7

8 New possibilities -> New costs The Swedish authority Lantmäteriet has estimated the costs to develop the new national elevation model to mkr (22-45 m ) depending on the ambition level of coverage and quality improvements in precision. Costs for WFD authorities? Presentationsnamn Namn 8

9 Driver climate scenario of Sweden The temperature will rise more in Sweden and Scandinavia than the global average. The mean temperature in Sweden may be 3-5 degrees higher in the 2080s. In the summer time we may have a warmer and drier climate, especially in southern Sweden. The winter temperatures may incrrease with 7 degrees in northern Sweden, and the surroundings of Stockholm will have a climate similar to the climate of today of northern France. The precipitation patterns change considerably, with increased Presentationsnamn Namn 9 precitipitation during autumn, winter and spring.

10 Consequences of a changed climate Heavier rains > more variation in water levels, more runoffs -> more floodings Calls for improved measures for safety plans for drinking water and wastewater facilities Calls for more detailed planning of hydromorphological measures Calls for careful planning of measures to minimize damage on houses and property (estimate that houses may be affected) Calls for measures in the coastal zone to adapt to sea level rise and coastal erosion Presentationsnamn Namn 10

11 Background Parameters Hydrological regime Regulation amplitude Regulation degree Changed high level flow Reduced low level flow Changes in continuity Artificial obstacles Degree of fragmentation Barrier effects Morphological changes Straightening/Clearing Soil use in watershed Soil use in vicinity Bridging roads L=Lakes, S=Streams L L, S L, S L, S L, S S S S L, S L, S S 11

12 Indicative way Assume that the degree of human impact indicates the ecological status Sum all data of impacts and indicators of impacts Analyse spatially with GIS Use expert opinions for some types of impacts Validate this for waters where impacts are considerable Presentationsnamn Namn 12

13 Why NHM? - nnhgrid2+ is a unified elevation model with its own technology and is the start on a new era of GIS analysis. It gives new possibilities for planning of localspecific measures and hydromorphological modelling with WFD Presentationsnamn Namn 13

14 What opportunities will NHM give? Adaptive edge zones Flooding zones Old meanders Former wetlands Suitable places for new wetland areas Placing of irrigation ponds Erosion areas Ditches in the landscape Presentationsnamn Namn 14

15 Measures against flooding Identify areas with high flooding risks Flood mapping potential water levels on maps Example Torne river Presentationsnamn Namn 16

16 Detailed flood mapping for the lower part of the River Torne 1. Data collection 2. Land survey (Land DEM) 3. River survey (River bed DEM) 4. Hydraulic model setup and calibration 5. Estimate Design Discharges 5a Statistical analysis Q100 and Q250 years. 5b.Hydrological Model QBHF 6. Run hydraulic model 7. Flood maps Source: Kristoffer Hallberg, SMHI Presentationsnamn Namn 17

17 Road bridges Road bridges and other artificial constructions over water surface areas break the algorithm for calculations of flow accumulation Presentationsnamn Namn 18

18 Are there any caveats? It is a lot of data! The data sets are not made for an ordinary PC, and not suitable for WFD work so far. - Geometries for water developed from nnhgrid2+ are not compatible with previous water layers from LM. - Existing ArcGIS toolsboxes seem to be not sophisticated enough for the purpose. Professional solutions such as Scop++, Lidar Analyst, EnviEx and others may be useful for som targetoriented solutions, with the disadvantage of being expensive Presentationsnamn Namn 19

19 ..contined How do we compare and valuate the results from NNHgrid2+ against older, more traditional calculations and data sets? or is this the start of a new era, and we have to just look into the future, and forget the older calculations? Presentationsnamn Namn 20

20 Any Finnish, Norwegian or Icelandic network with same purpose? Join the efforts Exchange ideas and applications Think out of the box Presentationsnamn Namn 21