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Bayerisches Landesamt für Umwelt

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


© LfU / Referat 62 / Lerchbaumer / 20.08.2012 2

German Levee Regulations with Regard to Vegetation + Theory and Practice Levee Vegetation Research Symposium, August 28-30, 2012

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)

http://de.wikipedia.org/w/index.php?title=Datei:Germany_in_the_European_Union_on_the_globe_(Europe_centered).svg&filetimestamp=20120322212244




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

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http://www.baw.de/en/die_baw/publikationen/merkblaetter/index.php.html




Standard Load Cases

permanent (BS-P) regular charged levees (i.e. HQ100) (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. HQ100 + 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




Hazards caused by Vegetation (Danube, August 1988)




Maintenance, Floodfighting and Survey




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"




Root Survey Program (1988-94)




Dry grasslands on Bavarian levees




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

13,8% defaults caused indirect by vegetation

9,8% rodent burrows,2,1% settlements and 1,8% cavitations (piping)

49,4% defaults caused direct by vegetation




Theory and Practice

Designed Plantation landscape architecture, slope protection

Uncontrolled Wilderness sustained deficient maintenance




Theory and Practice



non-critical if survey and maintenance is ensured




Theory and Practice



critical survey and maintenance deficient

Clearance Oversize Profils Substitution tolerable

Class-I/II-Levees Class-III-Levees

Classification Criteria ► levee heights and protected objects ► National Regulation ► flew depth and velocity, operative measures ► Bavarian Guideline




Theory and Practice

Designed Cultivation landscape architecture, slope protection


critical survey and maintenance deficient

Clearance Oversize Profils Substitution tolerable

Class-I/II-Levees Class-III-Levees




Clearances (Class-I/II-Levees)



crest inner slope levee protection strip




Clearances (Class-I/II-Levees)






Oversize Profiles (Reconstructions)

HWS Deggendorf-West (Donau) + LfU 2010




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




Reinforced Cuttoff-Walls (Bentonite-Cement-Slurries)

E DWA-M 512-1:2010 Bild 52

drilling technologies ► multiple drilling augers ► intersecting drilling slots by driving step method ► reinforcement by inserted steelpiles





E DWA-M 512-1:2010 Bild 52

drilling technologies ► single or double milling sword/s ► continuous milling wall ► reinforcement by inserted steelpiles





wall depth wall thickness

average daily output gauge

crosscut profiles overallweigth

compressive resistance

hydraulic gradient permeabilty

application

Drilling (MIP,DSM) 9,5/11,5 m 0,4 m 300 qm/d 3,0 m 20,0 m 45/55 to

min. 0,3 MPa non-statical min. 2,0 MPa statical and root-resistance min. 100 min. 10exp-8 m/s (Darcy)

granular soils

17,5/20,0 m 0,6 m 300 qm/d 4,5 m 26,0 m 120 to

max 9,5 m 0,35 to 1,0 m 800 to 1000 qm/d 3,0 m 4,0 m 70 to

Milling (FMI)




Case Study: Munich-Thalkirchen

HWS München-Thalkirchen (Isar) + SKI GmbH München 2005




Case Study: Munich-Thalkirchen




Munich-Thalkirchen (Isar)




Case Study: Munich-Thalkirchen (Isar)




Design Criteria (Load Cases)

inner-slope default profile due to tree-windfall

► arch-trust-effects ► pile interspaces 2-2.5m ► pile lengths 6-8m


Overtopping stability




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, …)

Costs-Relations



mineral sealings geotechnical sealings sheet piles cutoff-walls (mixed-in-place) cutoff-walls reinforced (mixed-in-place) diaphram-walls (mixed-in-plant)

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Floodplain Management

1930 1959

1999 1978




Floodplain Management

1930 1959

1978 1999




Floodplain Management Plans

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