Case study:Gadebridge park river restoration - Revision history

KStandbrook at 10:26, 25 February 2026

2026-02-25T10:26:42Z

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-{{Site
+{{Case study status
-|Name=Gadebridge Park
+|Approval status=Approved
 }}
 {{Location
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 *Engage with the local community in a variety of ways eg. project web page, mailing list updates, project mailbox, Facebook, Twitter, council newsletters, onsite signage, community events.
 }}
 {{Image gallery}}
 {{Case study image
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 |Subcatchment=Gade (Upper stretch Great Gaddesden to confluence with Bulbourne / GUC)
 }}
+{{Site
 {{Project background
 |Reach length directly affected=415
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 Five Rivers were subcontracted by BAM to undertake the ecological elements of the works- placement of gravels, planting etc.
 }}
+{{Motivations
+|Specific mitigation=Barriers to fish migration
 {{Hydromorphological quality elements header}}
 {{Hydromorphological quality element table row
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 |Quantitative monitoring=No
 |Control site used=Yes
-|Result=Awaiting results
+|Result=Improvement
 }}
 {{End table}}

KStandbrook at 15:13, 28 January 2026

2026-01-28T15:13:17Z

← Older revision		Revision as of 15:13, 28 January 2026
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	\|Average bankfull channel width category=10 - 50 m		\|Average bankfull channel width category=10 - 50 m
	\|Avrg bankfull channel width=10		\|Avrg bankfull channel width=10
			\|Average bankfull channel depth category=0.5 - 2 m
	\|Mean discharge category=0.1 - 1.0 m³/s		\|Mean discharge category=0.1 - 1.0 m³/s
	\|Mn discharge=0.16		\|Mn discharge=0.16

KStandbrook at 13:05, 28 January 2026

2026-01-28T13:05:31Z

← Older revision		Revision as of 13:05, 28 January 2026
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	\|River corridor land use=Urban, parkland, farmland		\|River corridor land use=Urban, parkland, farmland
	\|Average bankfull channel width category=10 - 50 m		\|Average bankfull channel width category=10 - 50 m
			\|Avrg bankfull channel width=10
	\|Mean discharge category=0.1 - 1.0 m³/s		\|Mean discharge category=0.1 - 1.0 m³/s
	\|Mn discharge=0.16		\|Mn discharge=0.16
	\|Average channel gradient category=0.001 - 0.01		\|Average channel gradient category=0.001 - 0.01
			\|Avrg channel gradient=0.0037
	}}		}}
	{{Location		{{Location

KStandbrook at 13:02, 28 January 2026

2026-01-28T13:02:05Z

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 {{Location
 |Location=51.77879, -0.49069
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 *Engage with the local community in a variety of ways eg. project web page, mailing list updates, project mailbox, Facebook, Twitter, council newsletters, onsite signage, community events.
 }}
-{{Site
 {{Motivations
 |Specific mitigation=Barriers to fish migration

Ascarr at 09:03, 28 January 2026

2026-01-28T09:03:00Z

← Older revision		Revision as of 09:03, 28 January 2026
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			{{Location
			\|Location=51.77879, -0.49069
			}}
	{{Project overview		{{Project overview
	\|Status=Complete		\|Status=Complete
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	\|Approval status=Approved		\|Approval status=Approved
	}}		}}
	~~{{Location~~
	~~\|Location=51.77879, -0.49069~~
	}}

	{{Image gallery}}		{{Image gallery}}

Ascarr at 09:02, 28 January 2026

2026-01-28T09:02:36Z

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 {{Project overview
 |Status=Complete
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 |Monitoring surveys and results=Baseline surveys undertaken for the project site pre-works:
-Macrophytes- dominated by marginal reeds and herbs, which choked much of the channel and the number of scoring taxa is very low. First record of water crowfoot at this site in 2024, but at cover value of 2 (1%). First record of lesser water-parsnip present at this site in 2024, but at cover value 1 (0.1%). INNS (Orange balsam) was recorded here in past surveys (2016 - 2023) at low cover, but not recorded in 2024. Suspected issues at this site could be turbidity, siltation/slow flow and poaching as the site is located in the park and popular for building temporary dams and children splashing in a summer. There were a limited number of Macrophytes species and a very homogenous community in the mill channel.
+*Macrophytes- dominated by marginal reeds and herbs, which choked much of the channel and the number of scoring taxa is very low. First record of water crowfoot at this site in 2024, but at cover value of 2 (1%). First record of lesser water-parsnip present at this site in 2024, but at cover value 1 (0.1%). INNS (Orange balsam) was recorded here in past surveys (2016 - 2023) at low cover, but not recorded in 2024. Suspected issues at this site could be turbidity, siltation/slow flow and poaching as the site is located in the park and popular for building temporary dams and children splashing in a summer. There were a limited number of Macrophytes species and a very homogenous community in the mill channel.
-Hyporheic zone- There were no specialist groundwater/hyporheic fauna recorded in any of the samples.
+*Hyporheic zone- There were no specialist groundwater/hyporheic fauna recorded in any of the samples.
-Water quality-  the water quality was both stable and at a high level across the two sites. There was little evidence of any pollution inputs impacting this stretch of the Gade and the low turbidity levels also show that there was minimal siltation / sedimentation issues.
+*Water quality-  the water quality was both stable and at a high level across the two sites. There was little evidence of any pollution inputs impacting this stretch of the Gade and the low turbidity levels also show that there was minimal siltation / sedimentation issues.
-River fly- Improvements are possible with restoration, aiming to increase abundances of caseless caddisflies, mayflies, and stoneflies.
+*River fly- Improvements are possible with restoration, aiming to increase abundances of caseless caddisflies, mayflies, and stoneflies.
-Invertebrates- Scored as Good status in 2017 and High status in 2018, 19, 21, 22 & 23.
+*Invertebrates- Scored as Good status in 2017 and High status in 2018, 19, 21, 22 & 23.
-Fish- in the 2021 survey we were suffering low flows. The highly modified old channel had no resilience in such conditions and offered very little habitat for fish during those flows. We confirmed this, as we recorded trout on a survey in 2022 further upstream, where restoration work had been carried out previously.
+*Fish- in the 2021 survey we were suffering low flows. The highly modified old channel had no resilience in such conditions and offered very little habitat for fish during those flows. We confirmed this, as we recorded trout on a survey in 2022 further upstream, where restoration work had been carried out previously.
 We have completed two water vole surveys a year since 2021 as they have been recorded both upstream and downstream of the park. We utilised camera traps and rafts from November 2023 and through 2024 and removed scrub/saplings to prevent the area from becoming overgrown and limiting water vole foraging opportunities. There had been no sightings of water vole for two years prior to construction.
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 *Engage with the local community in a variety of ways eg. project web page, mailing list updates, project mailbox, Facebook, Twitter, council newsletters, onsite signage, community events.
 }}
 {{Case study status
 |Approval status=Approved

KStandbrook at 11:41, 27 January 2026

2026-01-27T11:41:00Z

← Older revision		Revision as of 11:41, 27 January 2026
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	\|WFD water body name=Gade (Upper stretch Great Gaddesden to confluence with Bulbourne / GUC)		\|WFD water body name=Gade (Upper stretch Great Gaddesden to confluence with Bulbourne / GUC)
	\|Pre-project morphology=Impounded, Over deepened, Over-widened, Single channel, Straightened		\|Pre-project morphology=Impounded, Over deepened, Over-widened, Single channel, Straightened
	\|Reference morphology=2-stage channel~~, chalk stream~~, Pool-riffle, Sinuous		\|Reference morphology=2-stage channel, Pool-riffle, Sinuous, chalk stream
	\|Desired post project morphology=~~Pool~~-~~riffle, Sinuous~~, Groundwater dominated, 2-~~stage channel~~		\|Desired post project morphology=2-stage channel, Groundwater dominated, Pool-riffle, Sinuous
	\|Heavily modified water body=No		\|Heavily modified water body=No
	\|Protected species present=Yes		\|Protected species present=Yes
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	\|Dominant substrate=Silt		\|Dominant substrate=Silt
	\|River corridor land use=Urban, parkland, farmland		\|River corridor land use=Urban, parkland, farmland
			\|Mean discharge category=0.1 - 1.0 m³/s
			\|Mn discharge=0.16
	\|Average channel gradient category=more than 0.1		\|Average channel gradient category=more than 0.1
			\|Avrg channel gradient=0.33
	}}		}}
	{{Motivations		{{Motivations

KStandbrook at 11:18, 27 January 2026

2026-01-27T11:18:57Z

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 {{Motivations
 |Specific mitigation=Barriers to fish migration
@@ Line 105: / Line 122: @@
 |Subcatchment=Gade (Upper stretch Great Gaddesden to confluence with Bulbourne / GUC)
 }}
-{{Site
 {{Project background
 |Reach length directly affected=415

KStandbrook at 10:56, 27 January 2026

2026-01-27T10:56:12Z

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 {{Measures
 |Bank and bed modifications measure=1:3 and 1:6 banks, Introduction of spawning gravels, Creation of pools and riffles, creation of buffer zones, Creation of low flow channel, gravel river access point, preservation of historic mill leat
@@ Line 141: / Line 148: @@
 Five Rivers were subcontracted by BAM to undertake the ecological elements of the works- placement of gravels, planting etc.
 }}
-{{Motivations
 {{Hydromorphological quality elements header}}

KStandbrook at 10:49, 27 January 2026

2026-01-27T10:49:37Z

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 {{Project overview
 |Status=Complete
@@ Line 140: / Line 148: @@
 |Other motivation=Climate change resilience
 }}
-{{Measures
 {{Hydromorphological quality elements header}}
 {{Hydromorphological quality element table row