From a Defensive to an Integrated Approach Victor N
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01chap.qxd 5/4/09 10:26 AM Page 17 Copyright 2009 by Resources for the Future, in Water Policy in the Netherlands: Integrated Management in a Densely Populated Delta, edited by Stijn Reinhard and Henk Folmer. No part of this book chapter may be reproduced, distributed, or stored in any form or by any means (including photocopying, email, online posting, or electronic archiving on a disk drive or server) without the written permission of the Publisher. CHAPTER 1 From a Defensive to an Integrated Approach Victor N. de Jonge RESENT WATER MANAGEMENT policy and practice in the Netherlands have P been heavily influenced by a combination of the geological history of the country and the activities carried out by its inhabitants since about 2500 BP (years before present).The history of Dutch water policies began when the inhabitants of the coastal and floodplain areas tried to safeguard themselves and their livestock by building and living atop dwelling mounds.This was followed by the defensive and offensive periods, during which dikes were built, peat was excavated, and land was reclaimed for safety, living space, and agriculture. Quantitative water policy began in the 1200s, when farmers started organizing to combat flooding. Since then, local, and later also regional, water boards were formed. In the late 1960s, qualitative water policy was added to the existing quantitative policy.Two decades later, in the late 1980s, the focus of qualitative and quantitative water policies broad- ened to include the protection of aquatic ecosystems and sustainable economic development. This chapter describes the geological history of the Netherlands, the impact of humans on its aquatic environments, and the history of water management in the country.It provides the foundation for more detailed discussions in the chapters to follow. GEOLOGICAL HISTORY For a full understanding of the development of the Netherlands’ water policies, knowledge of the country’s origin and recent geological history is necessary.A combination of erosion, transport, and sedimentation processes created the basis for what is now the Netherlands.These processes were governed by wind, rivers, 17 01chap.qxd 5/4/09 10:26 AM Page 18 Copyright 2009 by Resources for the Future, in Water Policy in the Netherlands: Integrated Management in a Densely Populated Delta, edited by Stijn Reinhard and Henk Folmer. No part of this book chapter may be reproduced, distributed, or stored in any form or by any means (including photocopying, email, online posting, or electronic archiving on a disk drive or server) without the written permission of the Publisher. 18 • Victor N. de Jonge and the sea and were active during periods of marine transgressions (inundation of land due to a relative sea level rise) and regressions, in concert with the formation of ice sheets during glaciations and their melting in interglacial periods. During the Pliocene epoch, between 2,500,000 and 2,000,000 BP,the present area of the Netherlands was mainly a seabed.Around 200,000 BP,in the Saalian glaciation, the southern part of the region consisted of a polar desert (tundra), while the northern part was completely covered by an ice sheet. Important glacial depo- sitions occurred during this period.After the melting of the gigantic Saalian ice sheet in the interglacial period known as the Eemian, an area was left containing drumlins (hills of glacial drift), small and large stones, gravel, sand, till, boulder clay, and glacial water basins (de Mulder et al. 2003).The coldest period occurred circa 18,000 BP,during the end of the last glaciation in the Weichselian period.The entire North Sea area was a polar desert where, in addition to the previous role of water, eolian sediment transport (carried by the wind) was important. The European shoreline of the shallow North Sea area was shaped during the subsequent melting of the ice sheet and then inundation of seawater from what is now the northern North Sea and in the south through what is now the Strait of Dover (Ingólfsson n.d.).A relief-rich deltaic landscape developed, featuring rivers, moraine deposits, drumlins, gravel, sand, till, boulder clay, and loess derived from areas other than the Netherlands.The interaction among these elements, the wind, and the ongoing rapid sea level rise, a concomitant marine transgression, resulted in new marine and fluvial deposits. In addition, favorable conditions for the growth of wetland vegetations created the basis for future peat formation.The develop- ment of the North Sea shoreline between 9000 and 7800 BP,at the beginning of the Holocene, shows an ongoing fast marine transgression in the area now known as the Southern Bight. Between 8700 and 8300 BP,the British Isles became sepa- rated from the mainland of the European continent.The Dutch territory was then the area where the sea met some of the main European rivers. It was here, under increasing human influence and circumstances of sea level rise, tides, and river discharges, in concert with the growth of vegetation, that the landscape evolved into a dynamic coastal and delta area consisting of peat bogs and moors.According to Zagwijn (1991), these developments (see fig. 1.1) occurred over a relatively short period of 7,000 years.The post-Weichselian Dutch area changed from an open coast, with islands and tidal inlets connected to tidal flat water basins (5300 BP), to the mainly closed sandy coastline of today.A sea level rise between 7000 and 4000 BP inundated the lowest parts of the present Dutch territory, creating large lagoon and tidal flat systems fringed by extensive salt marshes (7000 to 5300 BP). Because of the ongoing sea level rise, this period was followed by further inundations. In the meantime, large peat bogs and moors formed on top of the Pleistocene sediments (3000 BP). Often marine clay was deposited on top of the peat and salt marshes, serving as a basis for the develop- ment of new salt marshes. Between 3000 and 2000 BP,the sea level showed stagnation and sometimes even a slight temporal decrease, indicating both regression and transgression peri- ods.The reduction in the rate of sea level rise allowed for important sand depo- sitions in the main tidal channels that connected the estuaries and lagoons with 01chap.qxd 5/4/09 10:26 AM Page 19 Copyright 2009 by Resources for the Future, in Water Policy in the Netherlands: Integrated Management in a Densely Populated Delta, edited by Stijn Reinhard and Henk Folmer. No part of this book chapter may be reproduced, distributed, or stored in any form or by any means (including photocopying, email, online posting, or electronic archiving on a disk drive or server) without the written permission of the Publisher. Chapter 1: From a Defensive to an Integrated Approach • 19 7000 BP 5300 BP 3000 BP Dunes and Salt marshes beach bars Peat and Water Peat moors clay Water Peat bogs Salt marshes Shallow tidal Fluviatile deposits flat systems 1900 BP 1500–1300 BP 1000–800 BP Vlie Lauwers Zee Flevo Lake Middel Zee Figure 1.1 Development of the Dutch area during the Holocene Source: Maps reproduced from Zagwijn 1991 with permission from Sdu Uitgeverij,‘s-Gravenhage, the Netherlands. the sea, diminishing the role of the tidal inlets. It also permitted the spread of veg- etation to cover extensive coastal wetlands, contributing to the modification of the landscape and serving as the basis for later peat formations. Part of the former com- plex of estuaries and lagoons, such as the centrally situated Flevo Lake (later named the Almere; fig. 1.1), became completely isolated from the sea.At the same time, the western coast started to develop into one extensive single beach bar, extend- ing to what is now the Vlie tidal inlet (fig.1.1).The Wadden Sea was also created. While a long, dune-rich coastal barrier was forming in the western part of the country,a new breakthrough occurred in the north, by which the freshwater Flevo Lake became connected to the sea again (de Mulder et al. 2003). Permanent human habitation in the coastal area was presumably possible from 2700 BP onward. After about 2000 BP,peat formation stopped as a result of drainage of the peat swamps both naturally,via the channel systems created during former sea inunda- tions, and because of human activities related to cultivation and peat excavation (de Mulder et al. 2003).The ultimate result was that circa 1700 BP,the sea inun- dated deeply into the coastal part of the country.A combination of peat excava- tion to obtain sea salt, peat erosion, natural drainage, peat oxidation and compaction 01chap.qxd 5/4/09 10:26 AM Page 20 Copyright 2009 by Resources for the Future, in Water Policy in the Netherlands: Integrated Management in a Densely Populated Delta, edited by Stijn Reinhard and Henk Folmer. No part of this book chapter may be reproduced, distributed, or stored in any form or by any means (including photocopying, email, online posting, or electronic archiving on a disk drive or server) without the written permission of the Publisher. 20 • Victor N. de Jonge (surface lowering), and large-scale erosion changed the southwestern region of the Netherlands from a peat-rich area into a system poor in peat but rich in channels and intertidal sand- and mudflats (de Mulder et al. 2003). WATER POLICY IN THE PAST When the river floodplains and coastal areas were first inhabited, water policy was nonexistent.Any action to safeguard people from flooding was realized locally by small, solitary groups of people and on an event-to-event basis rather than follow- ing an agreed master plan.This situation changed in the Middle Ages, when step by step the first flood defense measures were developed.