Southern England summary results - Revision history

Ajhil: /* Baseline groundwater quality data in the Palaeogene */

2026-10-21T11:44:23Z

Baseline groundwater quality data in the Palaeogene

← Older revision		Revision as of 11:44, 21 October 2026
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	<center>'''Baseline quality data for the Palaeogene in southern England'''</center>		<center>'''Baseline quality data for the Palaeogene in southern England'''</center>


	The water quality of oxidising Palaeogene groundwaters of near-neutral pH is, in the most part, good. High iron and manganese as well as slightly acidic conditions are characteristics of the Palaeogene groundwaters. In these more acidic groundwaters, mobilisation of some trace metals can occur. Some unconfined waters in the Palaeogene are influenced by agricultural activities, showing elevated nitrate (NO<sub>3</sub>.N) concentrations. The hydrochemical properties of the groundwaters in the Palaeogene aquifers are primarily determined by natural reactions between recharge water and the Palaeogene host rocks.		The water quality of oxidising Palaeogene groundwaters of near-neutral pH is, in the most part, good. High iron and manganese as well as slightly acidic conditions are characteristics of the Palaeogene groundwaters. In these more acidic groundwaters, mobilisation of some trace metals can occur. Some unconfined waters in the Palaeogene are influenced by agricultural activities, showing elevated nitrate (NO<sub>3</sub>.N) concentrations. The hydrochemical properties of the groundwaters in the Palaeogene aquifers are primarily determined by natural reactions between recharge water and the Palaeogene host rocks.

Ajhil: /* Baseline groundwater quality data in the Chalk of Dorset */

2026-10-21T11:44:14Z

Baseline groundwater quality data in the Chalk of Dorset

← Older revision		Revision as of 11:44, 21 October 2026
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	<center>'''Baseline quality data for the Lower Greensand in southern England'''</center>		<center>'''Baseline quality data for the Lower Greensand in southern England'''</center>


	The Dorset Chalk contains groundwater predominately of very high quality. However, much of the area is farmed, the long term effects of which have impacted on the natural groundwater quality. The main observed effect of agricultural activity has been the increase in nitrate (NO<sub>3</sub>.N) and potassium (K) over several decades. Apart from these examples, there is no evidence of widespread contamination from urban and rural wastes or other sources of pollution. Oxidising conditions found in the unconfined aquifer rapidly give way to a reducing environment as the aquifer becomes confined beneath Palaeogene deposits.		The Dorset Chalk contains groundwater predominately of very high quality. However, much of the area is farmed, the long term effects of which have impacted on the natural groundwater quality. The main observed effect of agricultural activity has been the increase in nitrate (NO<sub>3</sub>.N) and potassium (K) over several decades. Apart from these examples, there is no evidence of widespread contamination from urban and rural wastes or other sources of pollution. Oxidising conditions found in the unconfined aquifer rapidly give way to a reducing environment as the aquifer becomes confined beneath Palaeogene deposits.

Ajhil: /* Baseline groundwater quality data in the Lower Greensand */

2026-10-21T11:44:02Z

Baseline groundwater quality data in the Lower Greensand

← Older revision		Revision as of 11:44, 21 October 2026
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	\|}		\|}
	<center>'''Baseline quality data for the Lower Greensand in southern England'''</center>		<center>'''Baseline quality data for the Lower Greensand in southern England'''</center>


	The groundwater in the Lower Greensand is fresher than water from most other aquifers in the UK, mainly due to the relative purity of the sands and often short residence times. The low salinities of groundwater even in the deep confined parts of the aquifer show that it has been well flushed of any older water. Where the aquifer is confined, the groundwaters are more reducing and have higher iron concentrations.		The groundwater in the Lower Greensand is fresher than water from most other aquifers in the UK, mainly due to the relative purity of the sands and often short residence times. The low salinities of groundwater even in the deep confined parts of the aquifer show that it has been well flushed of any older water. Where the aquifer is confined, the groundwaters are more reducing and have higher iron concentrations.

Ajhil: /* Baseline groundwater quality data in the Chalk of the North Downs, Kent and east Surrey */

2026-10-21T11:43:53Z

Baseline groundwater quality data in the Chalk of the North Downs, Kent and east Surrey

← Older revision		Revision as of 11:43, 21 October 2026
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	\|}		\|}
	<center>'''Baseline quality data for the Chalk in the North Downs, Kent and east Surrey'''</center>		<center>'''Baseline quality data for the Chalk in the North Downs, Kent and east Surrey'''</center>


	The Chalk in this region generally contains water of high quality, the main properties being determined by natural reactions between rainwater and the carbonate rock (HCO<sub>3</sub>). Groundwater is oxidising in the unconfined areas, but becomes rapidly reducing once confined by the Palaeogene deposits. The confined groundwaters are typically fresh and of pristine pre-industrial quality but may contain residual concentrations of chloride (Cl) from older water at depth. Some unconfined Chalk groundwaters show the effects of pollution from industrial, domestic and agricultural sources.		The Chalk in this region generally contains water of high quality, the main properties being determined by natural reactions between rainwater and the carbonate rock (HCO<sub>3</sub>). Groundwater is oxidising in the unconfined areas, but becomes rapidly reducing once confined by the Palaeogene deposits. The confined groundwaters are typically fresh and of pristine pre-industrial quality but may contain residual concentrations of chloride (Cl) from older water at depth. Some unconfined Chalk groundwaters show the effects of pollution from industrial, domestic and agricultural sources.

Ajhil: /* Regional summary */

2026-10-21T11:43:40Z

Regional summary

← Older revision		Revision as of 11:43, 21 October 2026
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	<center>'''Geology of southern England'''</center>		<center>'''Geology of southern England'''</center>


	* The Chalk is a principal aquifer in southern England, used extensively for public water supply. It has a high porosity but low matrix permeability, and groundwater flows through a well-developed interconnected network of fractures. The Chalk outcrops in the Chilterns, North and South Downs, Salisbury Plain, Wessex Downs and on the south coast. It reaches a maximum thickness of 200 m.		* The Chalk is a principal aquifer in southern England, used extensively for public water supply. It has a high porosity but low matrix permeability, and groundwater flows through a well-developed interconnected network of fractures. The Chalk outcrops in the Chilterns, North and South Downs, Salisbury Plain, Wessex Downs and on the south coast. It reaches a maximum thickness of 200 m.

Ajhil: /* Baseline groundwater quality data in the Palaeogene */

2026-06-05T09:42:53Z

Baseline groundwater quality data in the Palaeogene

← Older revision		Revision as of 09:42, 5 June 2026
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	[[Image:SouthPalaeogeneBOX.jpg\|frameless\|center\|500px\|]]		[[Image:SouthPalaeogeneBOX.jpg\|frameless\|center\|500px\|]]
			<br>
	{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"		{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"
	\| '''Analysis'''		\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Analysis'''</span>
	\| '''Concentration (mg/l)'''		\| colspan="3" scope="col" style="width: 50px; background-color: #042e3f;" \| <span style="color:#ffffff"><center>'''Concentration (mg/l)'''</center>
	\|		\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Number of Samples'''</span>
	\|
	\| '''Number of ~~samples~~'''
	\|-		\|-
	\|		\| ! scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Minimum'''
	\| Minimum		\| ! scope="col" style="width: 50px; background-color: #042e3f;" \| <span style="color:#ffffff">'''Median'''
	\| Median		\| ! scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Maximum'''
	\| Maximum
	\|
	\|-		\|-
	\|Ca		\| ! scope="col" style="width: 200px;" \| Ca
	\|5.2		\| ! scope="col" style="width: 100px;" \| 5.2
	\|46.1		\| ! scope="col" style="width: 100px;" \| 46.1
	\|128		\| ! scope="col" style="width: 100px;" \| 128
	\|26		\| ! scope="col" style="width: 100px;" \| 26
	\|-		\|-
	\|Mg		\|Mg

Ajhil: /* Baseline groundwater quality data in the Palaeogene */

2026-06-05T09:41:03Z

Baseline groundwater quality data in the Palaeogene

← Older revision		Revision as of 09:41, 5 June 2026
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	===Baseline groundwater quality data in the Palaeogene===		===Baseline groundwater quality data in the Palaeogene===
	A summary of the baseline quality of groundwater in the Palaeogene is below. These data were collected as part of a collaborative project between BGS and the Environment Agency to investigate the [~~https://www2.bgs.ac.uk/~~groundwater~~/quality/BaselineUK/home.html/~~ baseline quality of groundwater in major UK aquifers]. The [~~https://www2.bgs.ac.uk/~~groundwater~~/quality/BaselineUK/home.html/~~ UK baseline study results] ~~results~~ page provides downloads of all the reports produced by the project.		A summary of the baseline quality of groundwater in the Palaeogene is below. These data were collected as part of a collaborative project between BGS and the Environment Agency to investigate the [[Baseline chemistry of groundwater in UK aquifers \| baseline quality of groundwater in major UK aquifers]]. The [[Baseline chemistry of groundwater in UK aquifers \| UK baseline study results]] page provides downloads of all the reports produced by the project.

	[[Image:SouthPalaeogeneBOX.jpg\|frameless\|center\|500px\|]]		[[Image:SouthPalaeogeneBOX.jpg\|frameless\|center\|500px\|]]

Ajhil: /* Baseline groundwater quality data in the Chalk of Dorset */

2026-06-05T09:40:06Z

Baseline groundwater quality data in the Chalk of Dorset

← Older revision		Revision as of 09:40, 5 June 2026
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	[[Image:SouthChalk59DorsetBOX.jpg\|frameless\|center\|500px\|]]		[[Image:SouthChalk59DorsetBOX.jpg\|frameless\|center\|500px\|]]
			<br>
	{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"		{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"
	\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Analysis'''</span>		\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Analysis'''</span>

Ajhil: /* Baseline groundwater quality data in the Chalk of Dorset */

2026-06-05T09:39:58Z

Baseline groundwater quality data in the Chalk of Dorset

← Older revision		Revision as of 09:39, 5 June 2026
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	===Baseline groundwater quality data in the Chalk of Dorset===		===Baseline groundwater quality data in the Chalk of Dorset===
	A summary of the baseline quality of groundwater in the Chalk of Dorset. These data were collected as part of a collaborative project between BGS and the Environment Agency to investigate the [~~https://www2.bgs.ac.uk/~~groundwater~~/quality/BaselineUK/home.html/~~ baseline quality of groundwater in major UK aquifers]. The [~~https://www2.bgs.ac.uk/~~groundwater~~/quality/BaselineUK/home.html/~~ UK baseline study results] page provides downloads of all the reports produced by the project.		A summary of the baseline quality of groundwater in the Chalk of Dorset. These data were collected as part of a collaborative project between BGS and the Environment Agency to investigate the [[Baseline chemistry of groundwater in UK aquifers \| baseline quality of groundwater in major UK aquifers]]. The [[Baseline chemistry of groundwater in UK aquifers \| UK baseline study results]] page provides downloads of all the reports produced by the project.

	[[Image:SouthChalk59DorsetBOX.jpg\|frameless\|center\|500px\|]]		[[Image:SouthChalk59DorsetBOX.jpg\|frameless\|center\|500px\|]]

	{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"		{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"
	\| '''Analysis'''		\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Analysis'''</span>
	\| '''Concentration (mg/l)'''		\| colspan="3" scope="col" style="width: 50px; background-color: #042e3f;" \| <span style="color:#ffffff"><center>'''Concentration (mg/l)'''</center>
	\|		\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Number of Samples'''</span>
	\|
	\| '''Number of ~~samples~~'''
	\|-		\|-
	\|		\| ! scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Minimum'''
	\| Minimum		\| ! scope="col" style="width: 50px; background-color: #042e3f;" \| <span style="color:#ffffff">'''Median'''
	\| Median		\| ! scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Maximum'''
	\| Maximum
	\|
	\|-		\|-
	\|Ca		\| ! scope="col" style="width: 200px;" \| Ca
	\|37		\| ! scope="col" style="width: 100px;" \| 37
	\|106		\| ! scope="col" style="width: 100px;" \| 106
	\|143		\| ! scope="col" style="width: 100px;" \| 143
	\|59		\| ! scope="col" style="width: 100px;" \| 59
	\|-		\|-
	\|Mg		\|Mg

Ajhil: /* Baseline groundwater quality data in the Lower Greensand */

2026-06-05T09:38:40Z

Baseline groundwater quality data in the Lower Greensand

← Older revision		Revision as of 09:38, 5 June 2026
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	[[Image:SouthLowerGreensandBOX.jpg\|frameless\|center\|500px\|]]		[[Image:SouthLowerGreensandBOX.jpg\|frameless\|center\|500px\|]]
			<br>
	{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"		{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"
	\| '''Analysis'''		\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Analysis'''</span>
	\| '''Concentration (mg/l)'''		\| colspan="3" scope="col" style="width: 50px; background-color: #042e3f;" \| <span style="color:#ffffff"><center>'''Concentration (mg/l)'''</center>
	\|		\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Number of Samples'''</span>
	\|
	\| '''Number of ~~samples~~'''
	\|-		\|-
	\|		\| ! scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Minimum'''
	\| Minimum		\| ! scope="col" style="width: 50px; background-color: #042e3f;" \| <span style="color:#ffffff">'''Median'''
	\| Median		\| ! scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Maximum'''
	\| Maximum
	\|
	\|-		\|-
	\|Ca
	\|9.3		\| ! scope="col" style="width: 200px;" \| Ca
	\|51.4		\| ! scope="col" style="width: 100px;" \| 9.3
	\|182		\| ! scope="col" style="width: 100px;" \| 51.4
	\|84		\| ! scope="col" style="width: 100px;" \| 182
			\| ! scope="col" style="width: 100px;" \| 84
	\|-		\|-
	\|Mg		\|Mg
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	\|84		\|84
	\|-		\|-
	\|Na 5		\|Na
			\| 5
	\|10.1		\|10.1
	\|111		\|111

← Older revision		Revision as of 09:40, 5 June 2026
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	[[Image:SouthChalk59DorsetBOX.jpg\|frameless\|center\|500px\|]]		[[Image:SouthChalk59DorsetBOX.jpg\|frameless\|center\|500px\|]]
			<br>
	{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"		{\|class="wikitable" style="background-color:#F0F8FF; margin:auto;"
	\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Analysis'''</span>		\| rowspan="2" scope="col" style="width: 100px;" style="background-color: #042e3f;" \| <span style="color:#ffffff">'''Analysis'''</span>