A social costs and benefits analysis of peat soil-subsidence towards 2100 in 4 scenarios
<p>Waternet is the executive agency of the regional water authority Amstel, Gooi and Vecht. Water authority Amstel, Gooi and Vecht manages the water levels (ditches) for 19 400 ha of peat meadows around the Netherlands capital Amsterdam. At present the ditches levels at a...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-04-01
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| Series: | Proceedings of the International Association of Hydrological Sciences |
| Online Access: | https://www.proc-iahs.net/382/669/2020/piahs-382-669-2020.pdf |
| Summary: | <p>Waternet is the executive agency of the regional water
authority Amstel, Gooi and Vecht. Water authority Amstel, Gooi and Vecht
manages the water levels (ditches) for 19 400 ha of peat meadows
around the Netherlands capital Amsterdam. At present the ditches levels at
about 40–60 cm beneath the peat meadow surface, resulting in a groundwater
level between from 30 until 80 cm below peat surface and a subsidence of
about 9 mm each year. A study was carried out on peat soil subsidence in the
Amstel, Gooi and Vecht water authority water management area towards 2100:
for short term effects (until 2027), midterm effects (until 2050) and longer
term effects (until 2100). This study explores 4 scenarios: (1) present
policy (maintain ditch waterlevel at maximum 60 cm below surface); (2) active
rewetting, groundwater level at surface; (3) passive rewetting, subsidence is
not compensated by lowering of water levels; (4) subsurface irrigation by
submerged drains (infiltration in summer, drainage in winter). The scenarios
are compared on farming, houses, public infrastructure, greenhouse gases and
water management.</p>
<p>At present, the total net benefit for farmers are EUR 7 million per year
for the whole area, while the costs for the water authority are EUR 37 million
per year for managing ditches, dikes and pumps. Costs for greenhouse
gases are EUR 18 million (at a price of EUR 40 per ton <span class="inline-formula">CO<sub>2</sub></span>-eq). Active
rewetting would reduce soil subsidence maximally from 2 to 0.5 m
towards 2100 but reduces the benefits for farming, whilst the costs for
water management stay alike. The costs for greenhouse gases however drops
with EUR 3 million per year immediately because <span class="inline-formula">CO<sub>2</sub></span>-eq emissions
drops. Best (financial) results (with respect to all stakeholders) on the
long term are booked by passive rewetting with lower costs for water
management, houses, public works and greenhouse gases. This scenario will
eventually take away the farming possibilities, but not before 2050 and
could be too slow to contribute strongly to Paris agreement goals. Best
result with respect to climate for short and long term is active rewetting,
which will drop the greenhouse gas emissions strongly (equivalent of EUR 2.3 million per year), reduce soil subsidence, but makes farming harder (drop
from 7.1 up to EUR 2.5 million per year benefit) and brings no direct reduction
of costs for the water authority. Best result on short term for farmers is
submerged infiltration drains. However, the effect of this scenario on GHG
emission is limited in this study.</p> |
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| ISSN: | 2199-8981 2199-899X |