GERMAN LEVEE REGULATIONS WITH REGARD TO VEGETATION THEORY AND PRATICE Uwe Kleber-Lerchbaumer + Bavarian Environment Agency Levee Vegetation Research Symposium August 28-30, 2102 Sacramento/CA
Introduction Bavaria Population: 12,559 Mio. (Germany: 81,844 Mio.) Area: 70.552 km² (Germany: 357.121 km²) Capital: Munich Bavarian State Flood-Protection-Works Levees: 1350 km Flood-Protection Walls: 180 km Mobile Flood-Protection Systems: 16 km Dams: 24 (180.000.000 m³) Flood Storage Polder: 1 (6.500.000 m³) (5 projected) Bavarian Watermanagement Administration State State Ministry of Environment & Public Health Bavarian Environment Agency Region District Councils (7) Local State Water Departements (17) 2
German Levee Regulations Regulations DIN 19712 Flood-Protection-Works (2012) Codes of Practice (Guidelines) DWA-M 507-1 Levees Part 1: Design, Construction and Operation (2011) DWA-M 507-2 Levees Part 2: Ecological Aspects (in progress) BAW-MSD 2011 Dams on Waterway www.baw.de/en/die_baw/publikationen/merkblaetter/index.php.html? 3
Standard Load Cases permanent (BS-P) regular charged levees (i.e. HQ 100 ) (saftey factor 1.5/1.7) temporary (BS-T) inspections and construction period (saftey factor 1.3/1.5) accidental (BS-A) non-regular/extraordinary flood events (saftey factor 1.1/1.3) fully charged levee (i.e. HQ 100 + freeboard) (A.1) failure of structural elements based on regular design flood (A.2) cutoff walls, drainage systems, slope failures erosion, inner erosion and windfall events practicability access and visuabilty maintenance, floodfighting and survey 4
Hazards caused by Vegetation (Danube, August 1988) 5
Maintenance, Floodfighting and Survey 6
Levee regulations with regard to vegetation levee surfaces must be permanently erosion-resistant waterside slopes (regular) with regard to incident flow inner slopes (extraordinary) with regard to overtopping events levee surfaces must be adapted to regular maintenance, survey and floodfighting German Standard Regulation levees and both-sided levee protection strips (regular 5m) must be designed with compact grass/swards coverage rate, root density kept without woody vegetation permanently (poplars 20m) Exceptions rootstocks kept out of statical required profile zones permanently oversize profiles (reconstruction) and constructural substitutions (restoration) classification to low hazard potential adapted and "normal-grown trees" and shrubs on upper parts of inland slopes if overtopping is impossible if maintenance, survey and floodfighting is required vegetation kept in "good state" 7
Root Survey Program (1988-94) 8
Dry grasslands on Bavarian levees 9
Monitoring and Survey of Levees in Bavaria Regular Maintenance and Documentation annual survey State Water Departements annual levee saftey reports Bavarian Environment Agency measures required compulsory Design criteria and stability proofs periodical evaluation State Water Departements, Bavarian Environment Agency floodrisk management plans (EC-FRMD) Bavarian Environment Agency priorization State Ministry of Environment and Public Health restoration or reconstruction projects non-compulsory Public Saftey measures to prevent hazards and to ensure public uses tree survey and arboriculture frequentley personal liability compulsory 49,4% defaults caused direct by vegetation 13,8% defaults caused indirect by vegetation 9,8% rodent burrows,2,1% settlements and 1,8% cavitations (piping) 10
Theory and Practice Designed Plantation landscape architecture, slope protection Uncontrolled Wilderness sustained deficient maintenance 11
Theory and Practice Designed Plantation landscape architecture, slope protection Uncontrolled Wilderness sustained deficient maintenance non-critical if survey and maintenance is ensured 12
Theory and Practice Designed Plantation landscape architecture, slope protection Uncontrolled Wilderness sustained deficient maintenance critical survey and maintenance deficient Class-I/II-Levees Class-III-Levees Clearance Oversize Profils Substitution tolerable Classification Criteria levee heights and protected objects National Regulation flew depth and velocity, operative measures Bavarian Guideline 13
Theory and Practice Designed Cultivation landscape architecture, slope protection Uncontrolled Wilderness sustained deficient maintenance critical survey and maintenance deficient Class-I/II-Levees Class-III-Levees Clearance Oversize Profils Substitution tolerable 14
Clearances (Class-I/II-Levees) Designed Plantation landscape architecture, slope protection Uncontrolled Wilderness sustained deficient maintenance crest inner slope levee protection strip 15
Clearances (Class-I/II-Levees) Designed Plantation landscape architecture, slope protection Uncontrolled Wilderness sustained deficient maintenance 16
Oversize Profiles (Reconstructions) HWS Deggendorf-West (Donau) + LfU 2010 17
Constructural Substitutions requirements erosion-resistant stability sheet pile systems cutoff-wall systems, reinforced diaphragm-wall systems, reinforced Mixed-in-Place Slurries 150/170-350/800 kg/m³ cement (CEMIII) 25/30-50 kg/m/m³ bentonite 600/800-700/900 kg/m³ water additional fillers (rock meal/flour, sand, ) mixed with original soils drilling technologies milling technologies sheet piles cuttoff-walls root-resistance 18
Reinforced Cuttoff-Walls (Bentonite-Cement-Slurries) drilling technologies multiple drilling augers intersecting drilling slots by driving step method reinforcement by inserted steelpiles E DWA-M 512-1:2010 Bild 52 19
Reinforced Cuttoff-Walls (Bentonite-Cement-Slurries) drilling technologies single or double milling sword/s continuous milling wall reinforcement by inserted steelpiles E DWA-M 512-1:2010 Bild 52 20
Reinforced Cuttoff-Walls (Bentonite-Cement-Slurries) 21
Reinforced Cuttoff-Walls (Bentonite-Cement-Slurries) wall depth wall thickness average daily output gauge crosscut profiles overallweigth Drilling (MIP,DSM) 9,5/11,5 m 0,4 m 300 qm/d 3,0 m 20,0 m 45/55 to 17,5/20,0 m 0,6 m 300 qm/d 4,5 m 26,0 m 120 to Milling (FMI) max 9,5 m 0,35 to 1,0 m 800 to 1000 qm/d 3,0 m 4,0 m 70 to compressive resistance hydraulic gradient permeabilty application min. 0,3 MPa non-statical min. 2,0 MPa statical and root-resistance min. 100 min. 10exp-8 m/s (Darcy) granular soils 22
Case Study: Munich-Thalkirchen HWS München-Thalkirchen (Isar) + SKI GmbH München 2005 23
Case Study: Munich-Thalkirchen 24
Munich-Thalkirchen (Isar) 25
Case Study: Munich-Thalkirchen (Isar) 26
Design Criteria (Load Cases) arch-trust-effects pile interspaces 2-2.5m pile lengths 6-8m inner-slope default profile due to tree-windfall 27
Overtopping stability 28
Costs-Relations construction costs (restoration) 200-500 EUR/m conventional earthwork 500-1200 EUR/m reinforced cutoff-walls monetary profits less land acquisation less compensation measures for clearances (environmental and forestry law) less application standards less operating costs possible non-monetary profits non-erosive system (burrowing rodents and mammals, ) overtopping stability competitively uses (recreation, ) mineral sealings? geotechnical sealings sheet piles cutoff-walls (mixed-in-place) cutoff-walls reinforced (mixed-in-place) diaphram-walls (mixed-in-plant) 29
Floodplain Management 1930 1959 1978 1999 30
Floodplain Management 1930 1959 1978 1999 31
Floodplain Management Plans 32
Floodplain Management Plans 33