The Noads Mire

Summary

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Wetland restoration at Noads Mire in the New Forest was monitored using geomorphological surveys and fixed-point photography, funded through the Higher Level Stewardship scheme. Artificial drainage had caused excessive erosion, so work from 2017 to 2020 infilled the drain, raised the bed level, levelled spoil banks to reconnect the floodplain, and later moved the channel back toward its original route downstream of a ford. Early recovery was slowed by thin soils, limited vegetation, and heavy rainfall, leading to visible erosion and follow-up repairs in 2022, including replacing slumped heather bales and infilling scoured pools with local gravels. Comparisons of 2017 and 2024 surveys show a shift to more diffuse flow, fewer actively eroding areas, wider and shallower channel forms in many sections, and increased in-channel vegetation. Longer-term benefits such as peat formation from Sphagnum are anticipated.
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The Noads Mire – case study: Monitoring wetland restoration in the New Forest using fixed point photography and geomorphological surveys

Overview:

Since 2010, the Higher Level Stewardship (HLS) scheme has been funding wetland restoration projects across the New Forest. To monitor the progress of these efforts, geomorphological surveys and fixed-point photography have been employed. One example project is The Noads Mire, where artificial drainage had been causing excessive erosion.

The surveys demonstrated that the restoration work was successful in creating a watercourse with a more diffuse flow, reducing areas of active erosion and enabling water to spread out laterally. The hydrological and ecological benefits of this are numerous. Some, such as the formation of peat from newly established Sphagnum moss, will only become evident in the long term. However, other benefits, like the increased growth of vegetation within the channels, are already visible.

Background:

Restoration work initially took place between 2017 and 2020. This involved infilling the artificial drain line running through the mire and raising the bed level, so that it grades into a shallow stream through the wooded area. This was done using heather bales and hoggin (locally dug gravels), and covering this using material from the spoil banks, which were levelled out to restore floodplain connectivity. Further restoration work took place downstream of the ford crossing, in which the watercourse was relocated back to its original route (where a remnant meanders were visible).

Thinness of the soil and scarcity of natural vegetation, coupled with heavy rainfall events shortly after restoration, meant initial recovery post restoration was slower than hoped, and areas of active erosion were clearly visible. Therefore, in 2022, repair work was done to fix areas where heather bales had decomposed and slumped, and small sections were eroding. This involved removing heather bale stakes and infilling scoured pools with hoggin and gravels.

Today, the area has visibly benefitted from the restoration work, as demonstrated by the fixed point photography and geomorphological data, collected before and after restoration.

The Noads

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Table 1: Channel dimensions

Survey number Date Channel width (cm) Left Bank Height (cm) Right Bank Height (cm) Water width (cm) Water depth (cm)
108/20170.500.670.810.40.05
106/20241.500.10.10.80.06
208/20170.900.440.540.80.07
206/20241.080.250.380.080.08
308/20170.300.750.760.30.06
306/20242.100.180.290.80.09
408/20171.001.391.230.450.02
406/20242.950.360.292.40.09
508/20171.501.31.1310.02
506/20243.001.31.132.740.04
608/20171.201.431.430.80.03
606/20243.071.431.431.40.04
708/20171.600.860.720.70.02
706/20241.20.860.721.20.08
808/20170.70.060.050.50.03
806/2024>5 (multiple channels)0.050.05>5 (multiple channels)0.04
908/20172.10.380.430.20.09
906/20242.50.100.101.40.05
1008/20171.21.101.100.60.16
1006/20242.70.100.101.150.08

Table 2: Geomorphology survey results. Presence of flow types, bank profiles, sediment types.

Flow types present Dominant flow type Bank profiles present Dominant bank profile type Sediment types present Dominant sediment type
08/2017 No perceptible flow, smooth, rippled, chute, free flow Smooth Composite, Gentle (<45°), Vertical, vertical with undercut Gentle Earth, clay, silt sand, gravel-pebble Peat and gravel-pebble
06/2024 No perceptible flow, smooth, rippled Smooth Composite, Gentle (<45°), Steep (>45°) Gentle Peat, silt, sand, gravel-pebble, cobble Peat and gravel-pebble

Table 3: Geomorphology survey results. In channel vegetation.

Survey number Date In-channel vegetation abundance
108/2017R
106/2024D
208/2017R
206/2024F
308/2017NP
306/2024D
408/2017NP
406/2024A
508/2017NP
506/2024F
608/2017R
606/2024A
708/2017NP
706/2024A
808/2017D
806/2024D
908/2017D
906/2024D
1008/2017D
1006/2024D

Channel vegetation abundance was recorded according to the DAFOR scale. D – Dominant (> covers 75% channel), A – abundant (50-75%), F – frequent (25-50%), O – occasional (5-25%), R (< 5%). NP – not present

Key and glossary:

Name Description
BedrockBare bedrock exposed at surface
BoulderMineral particles, diameter > 256 mm (head sized)
CobbleMineral particles, diameter 64-256 mm (fist sized)
Gravel-pebbleMineral particles, diameter 2-64 mm
SandMineral particles, diameter 0.0625-2 mm
SiltMineral particles, diameter 0.00195-0.0625 mm
ClayMineral particles, diameter < 0.00195 mm
OrganicDead plant material that is intact or only lightly decomposed
PeatPlant material that is largely decomposed and has accumulated in a water-saturated environment in the absence of oxygen
EarthMixture of mineral and organic particle sizes (mainly sand and finer with occasional gravel)
  • Vertical
  • Vertical with overhang
  • Vertical with undercut
  • Vertical with toe
  • Steep (>45°)
  • Gentle (<45°)
  • Composite

Flow Types

  • Free fall
  • Chute
  • Broken standing waves
  • Unbroken standing waves
  • Upwelling
  • Rippled
  • Smooth
  • No perceptible flow
  • Dry