Case Study Land Cover Change Groundwater Niger - Revision history

LaurenGiles: /* Sources */ Favreau et al 2003 link

2024-01-22T11:56:01Z

Sources: Favreau et al 2003 link

← Older revision		Revision as of 12:56, 22 January 2024
Line 62:		Line 62:
	Favreau G, Cappelaere B, Massuel S, Leblanc M, Boucher M, Boulain N and Leduc C. 2009. Land clearing, climate variability, and water resources increase in semiarid southwest Niger: A review. Water Resources Research, 45 (7).		Favreau G, Cappelaere B, Massuel S, Leblanc M, Boucher M, Boulain N and Leduc C. 2009. Land clearing, climate variability, and water resources increase in semiarid southwest Niger: A review. Water Resources Research, 45 (7).

	Favreau G, Leduc C, Seidel JL, Ousmane SD and Mariotti ANDRÉ. 2003. [~~http~~://~~hydrologie~~.~~org~~/~~redbooks~~/~~a278/iahs_278_163.pdf~~ Land clearance and nitrate-rich groundwater in a Sahelian aquifer, Niger]. International Association of Hydrological Sciences Publication (278) 163-167.		Favreau G, Leduc C, Seidel JL, Ousmane SD and Mariotti ANDRÉ. 2003. [https://www.researchgate.net/publication/228804140_Land_clearance_and_nitrate-rich_groundwater_in_a_Sahelian_aquifer_Niger Land clearance and nitrate-rich groundwater in a Sahelian aquifer, Niger]. International Association of Hydrological Sciences Publication (278) 163-167.

	Leblanc MJ, Favreau G, Massuel S, Tweed SO, Loireau M and Cappelaere B. 2008. [~~http~~://www.sciencedirect.com/science/article/pii/S0921818107001336 Land clearance and hydrological change in the Sahel: SW Niger]. Global and Planetary Change, 61 (3), 135-150. doi: 10.1016/j.gloplacha.2007.08.011		Leblanc MJ, Favreau G, Massuel S, Tweed SO, Loireau M and Cappelaere B. 2008. [https://www.sciencedirect.com/science/article/pii/S0921818107001336 Land clearance and hydrological change in the Sahel: SW Niger]. Global and Planetary Change, 61 (3), 135-150. doi: 10.1016/j.gloplacha.2007.08.011

	Torou BM, Favreau G, Barbier B, Pavelic P, Illou M and Sidibé F. 2013. Constraints and opportunities for groundwater irrigation arising from hydrologic shifts in the Iullemmeden Basin, south-western Niger. Water international, 38 (4), 465-479. doi: 10.1080/02508060.2013.817042		Torou BM, Favreau G, Barbier B, Pavelic P, Illou M and Sidibé F. 2013. Constraints and opportunities for groundwater irrigation arising from hydrologic shifts in the Iullemmeden Basin, south-western Niger. Water international, 38 (4), 465-479. doi: 10.1080/02508060.2013.817042

LaurenGiles: /* Impact on livelihoods */ grammar - previously 'water or land or tenure insecurity'

2023-11-27T11:56:41Z

Impact on livelihoods: grammar - previously 'water or land or tenure insecurity'

← Older revision		Revision as of 12:56, 27 November 2023
Line 52:		Line 52:
	Incomes from groundwater irrigated vegetable farming are low – only 5 to 15% of incomes from rainfed agriculture. The majority of farmers concentrate their labour on field cropping in the rainy season, leaving the gardens. Yet the opportunity cost of labour in the dry season is also low, not least because political instability in Cote d’Ivoire and northern Nigeria has disrupted traditional seasonal labour migration to those countries. This low cost of dry season labour is one reason that irrigated vegetable farming persists. Another is that, although irrigated vegetable farming does not necessarily substantially raise incomes, it does help maintain food security.		Incomes from groundwater irrigated vegetable farming are low – only 5 to 15% of incomes from rainfed agriculture. The majority of farmers concentrate their labour on field cropping in the rainy season, leaving the gardens. Yet the opportunity cost of labour in the dry season is also low, not least because political instability in Cote d’Ivoire and northern Nigeria has disrupted traditional seasonal labour migration to those countries. This low cost of dry season labour is one reason that irrigated vegetable farming persists. Another is that, although irrigated vegetable farming does not necessarily substantially raise incomes, it does help maintain food security.

	Vegetable cultivation is not constrained by a lack of water or land or tenure insecurity – land cover change continues and groundwater levels continue to rise. Rather, there is a capital constraint on farmers acquiring the inputs to expand their enterprises. These include fertilisers, pesticides and in particular fencing materials to protect their crops from grazing animals. One way that some people have overcome this constraint is by obtaining loans from NGOs that have drilled boreholes.		Vegetable cultivation is not constrained by a lack of water, land or tenure insecurity – land cover change continues and groundwater levels continue to rise. Rather, there is a capital constraint on farmers acquiring the inputs to expand their enterprises. These include fertilisers, pesticides and in particular fencing materials to protect their crops from grazing animals. One way that some people have overcome this constraint is by obtaining loans from NGOs that have drilled boreholes.


	===The future?===		===The future?===

Beod at 11:00, 2 July 2019

2019-07-02T11:00:07Z

← Older revision		Revision as of 12:00, 2 July 2019
Line 1:		Line 1:
	[[Africa Groundwater Atlas Home \| Africa Groundwater Atlas]] >> [[Additional resources \| Additional resources]] >> [[Case studies \| Case studies]] or [[Groundwater irrigation in Africa \| Groundwater and irrigation in Africa]] >> Case study: Land cover changes and impacts on groundwater in southwest Niger		[[Africa Groundwater Atlas Home \| Africa Groundwater Atlas]] >> [[Additional resources \| Additional resources]] >> [[Case studies \| Case studies]] or [[Groundwater irrigation in Africa \| Groundwater and irrigation in Africa]] >> Case study: Land cover changes and impacts on groundwater in southwest Niger

	Please cite page as: Africa Groundwater Atlas. 2019. Case study: Land cover changes and impacts on groundwater in southwest Niger		Please cite page as: Africa Groundwater Atlas. 2019. Case study: Land cover changes and impacts on groundwater in southwest Niger. British Geological Survey. Accessed [date you accessed the information]. ''Weblink''.
	. British Geological Survey. Accessed [date you accessed the information]. ''Weblink''.

Beod at 10:58, 2 July 2019

2019-07-02T10:58:52Z

← Older revision		Revision as of 11:58, 2 July 2019
Line 1:		Line 1:
	[[Africa Groundwater Atlas Home \| Africa Groundwater Atlas]] >> [[Additional resources \| Additional resources]] >> [[Case studies \| Case studies]] or [[Groundwater irrigation in Africa \| Groundwater and irrigation in Africa]] >> Case study: Land cover changes and impacts on groundwater in southwest Niger		[[Africa Groundwater Atlas Home \| Africa Groundwater Atlas]] >> [[Additional resources \| Additional resources]] >> [[Case studies \| Case studies]] or [[Groundwater irrigation in Africa \| Groundwater and irrigation in Africa]] >> Case study: Land cover changes and impacts on groundwater in southwest Niger

			Please cite page as: Africa Groundwater Atlas. 2019. Case study: Land cover changes and impacts on groundwater in southwest Niger
			. British Geological Survey. Accessed [date you accessed the information]. ''Weblink''.

Beod at 13:33, 17 April 2018

2018-04-17T13:33:13Z

← Older revision		Revision as of 14:33, 17 April 2018
Line 24:		Line 24:
	===Local hydrogeology===		===Local hydrogeology===

	The local aquifer is part of the Continental Terminal formation of Tertiary age, within the Iullemeden Basin, , which outcrops over a large part of southwest Niger and neighbouring countries. The aquifer comprises loosely cemented clays, silts and sands, and is unconfined.		The local aquifer is part of the Continental Terminal formation of Tertiary age, within the Iullemeden Basin, which outcrops over a large part of southwest Niger and neighbouring countries. The aquifer comprises loosely cemented clays, silts and sands, and is unconfined.

	For more information on the hydrogeology of this aquifer, see the [http://earthwise.bgs.ac.uk/index.php/Hydrogeology_of_Niger Hydrogeology of Niger] page.		For more information on the hydrogeology of this aquifer, see the [http://earthwise.bgs.ac.uk/index.php/Hydrogeology_of_Niger Hydrogeology of Niger] page.
Line 33:		Line 33:
	The changes in land cover and surface water drainage patterns have led to an increase in groundwater recharge rates, and a corresponding rise in groundwater levels. Groundwater recharge has increased from 1 to 5 mm/year in the 1950s to more than 20 mm/year in the 1990s. Groundwater levels rose by an average of ~4m/year between 1963 and 2005.		The changes in land cover and surface water drainage patterns have led to an increase in groundwater recharge rates, and a corresponding rise in groundwater levels. Groundwater recharge has increased from 1 to 5 mm/year in the 1950s to more than 20 mm/year in the 1990s. Groundwater levels rose by an average of ~4m/year between 1963 and 2005.

	The increase in recharge has in the past been attributed largely to a reduction in evapotranspiration from vegetation surfaces due to the changes in vegetation cover. The recent studies suggest that the increase in gullies and ponds and increased surface water drainage density is more likely to be the main driver of increased recharge. Surface runoff during rainfall events flows to sandy gullies and ponds, where it is temporarily stored – the internal nature of the surface water drainage network means that runoff doesn’t leave the catchment. The sandy~~, permeable based~~ of these gullies and ponds ~~then~~ allows ready infiltration of this runoff to the sedimentary aquifer.		The increase in recharge has in the past been attributed largely to a reduction in evapotranspiration from vegetation surfaces due to the changes in vegetation cover. The recent studies suggest that the increase in gullies and ponds and increased surface water drainage density is more likely to be the main driver of increased recharge. Surface runoff during rainfall events flows to sandy gullies and ponds, where it is temporarily stored – the internal nature of the surface water drainage network means that runoff doesn’t leave the catchment. The permeable sandy base of these gullies and ponds allows ready infiltration of this runoff to the sedimentary aquifer.

	A connected change has been an increased concentration of nitrate in groundwater, which is seen preferentially close to the gullies and ponds. Nitrate values of over 50 mg/l have been recorded, exceeding the WHO recommended limit for drinking water. Isotopic concentrations in groundwater and in soil show that this is not due to pollution from sewage or agriculture: it is due to increased leaching of biologically fixed nitrate from the soil. The correlation of high nitrate with the presence of the ponds and gullies that are sources of recharge indicates that surface runoff is indeed the source of nitrate.		A connected change has been an increased concentration of nitrate in groundwater, which is seen preferentially close to the gullies and ponds. Nitrate values of over 50 mg/l have been recorded, exceeding the WHO recommended limit for drinking water. Isotopic concentrations in groundwater and in soil show that this is not due to pollution from sewage or agriculture: it is due to increased leaching of biologically fixed nitrate from the soil. The correlation of high nitrate with the presence of the ponds and gullies that are sources of recharge indicates that surface runoff is indeed the source of nitrate.
Line 40:		Line 40:
	===Groundwater for irrigation===		===Groundwater for irrigation===

	This change in the local groundwater system has implications for human use of groundwater. Groundwater use in this area was initially relatively ~~small~~, largely for domestic use and livestock watering. However, since 2000, groundwater has been increasingly used for small scale vegetable irrigation, with onions, tomatoes and cabbage being important crops grown in small gardens. The increased recharge supports this increase in groundwater abstraction.		This change in the local groundwater system has implications for human use of groundwater. Groundwater use in this area was initially relatively limited, largely for domestic use and livestock watering. However, since 2000, groundwater has been increasingly used for small scale vegetable irrigation, with onions, tomatoes and cabbage being important crops grown in small gardens. The increased recharge supports this increase in groundwater abstraction.

	This irrigated vegetable cultivation mostly takes place in the dry season, using shallow wells dug by the irrigators themselves. Richer farmers can afford to line their wells with cement. There are a few deep drilled boreholes, more usually drilled by NGOs or the government, and these are used for drinking water. Water is generally extracted from shallow wells using buckets and from deeper wells using mechanical hand and foot pumps. Irrigators rely on water cans for application to crops.		This irrigated vegetable cultivation mostly takes place in the dry season, using shallow wells dug by the irrigators themselves. Richer farmers can afford to line their wells with cement. There are a few deep drilled boreholes, more usually drilled by NGOs or the government, and these are used for drinking water. Water is generally extracted from shallow wells using buckets and from deeper wells using mechanical hand and foot pumps. Irrigators rely on water cans for application to crops.

Beod at 10:03, 28 March 2018

2018-03-28T10:03:52Z

← Older revision		Revision as of 11:03, 28 March 2018
Line 1:		Line 1:
	[[Africa Groundwater Atlas Home \| Africa Groundwater Atlas]] >> [[Additional resources \| Additional resources]] >> [[Case studies \| Case studies]] or [[Groundwater irrigation in Africa \| Groundwater and irrigation in Africa]] >> Case study: Land cover changes and impacts on groundwater in southwest Niger		[[Africa Groundwater Atlas Home \| Africa Groundwater Atlas]] >> [[Additional resources \| Additional resources]] >> [[Case studies \| Case studies]] or [[Groundwater irrigation in Africa \| Groundwater and irrigation in Africa]] >> Case study: Land cover changes and impacts on groundwater in southwest Niger


			Go to the [[Hydrogeology of Niger \| '''Hydrogeology of Niger''']] page.

Beod: /* Agriculture and land cover change in Niger */

2018-03-27T08:58:13Z

Agriculture and land cover change in Niger

← Older revision		Revision as of 09:58, 27 March 2018
Line 18:		Line 18:
	Alongside this change in vegetation cover, this area saw a marked increase in the presence of sandy gullies and ponds, which form an internal surface water drainage network. Aerial photographs show a ~2.5 fold increase in drainage density between 1950 and 1992.		Alongside this change in vegetation cover, this area saw a marked increase in the presence of sandy gullies and ponds, which form an internal surface water drainage network. Aerial photographs show a ~2.5 fold increase in drainage density between 1950 and 1992.

	[[File:MilletFarmingNiger.jpg\|thumb\| 400 px\| center\| Contemporary land use in Niger: millet farming and cattle herding. Figure source: [https://www.flickr.com/photos/icrisat/7182985943/in/album-72157630100501968/ ICRISAT / M. Winslow]]		[[File:MilletFarmingNiger.jpg\|thumb\| 400 px\| center\| Contemporary land use in Niger: millet farming and cattle herding. Figure source: [https://www.flickr.com/photos/icrisat/7182985943/in/album-72157630100501968/ ICRISAT / M. Winslow]]]

	===Local hydrogeology===		===Local hydrogeology===

Beod: /* Agriculture and land cover change in Niger */

2018-03-27T08:57:59Z

Agriculture and land cover change in Niger

← Older revision		Revision as of 09:57, 27 March 2018
Line 18:		Line 18:
	Alongside this change in vegetation cover, this area saw a marked increase in the presence of sandy gullies and ponds, which form an internal surface water drainage network. Aerial photographs show a ~2.5 fold increase in drainage density between 1950 and 1992.		Alongside this change in vegetation cover, this area saw a marked increase in the presence of sandy gullies and ponds, which form an internal surface water drainage network. Aerial photographs show a ~2.5 fold increase in drainage density between 1950 and 1992.

	[[File:MilletFarmingNiger.jpg\|thumb\| 400 px\| center\| Contemporary land use in Niger: millet farming and cattle herding. Figure source: ~~[http://peoplefoodandnature.org/blog/global-landscape-restoration-the-art-of-the-do-able/ Landscapes for People, Food and Nature 2014] / ICRISAT/M. Winslow on~~ [https://www.flickr.com/photos/icrisat/ ~~Flickr]~~ ]]		[[File:MilletFarmingNiger.jpg\|thumb\| 400 px\| center\| Contemporary land use in Niger: millet farming and cattle herding. Figure source: [https://www.flickr.com/photos/icrisat/7182985943/in/album-72157630100501968/ ICRISAT / M. Winslow]]

	===Local hydrogeology===		===Local hydrogeology===

Beod: /* Agriculture and land cover change in Niger */

2018-03-27T08:54:19Z

Agriculture and land cover change in Niger

← Older revision		Revision as of 09:54, 27 March 2018
Line 18:		Line 18:
	Alongside this change in vegetation cover, this area saw a marked increase in the presence of sandy gullies and ponds, which form an internal surface water drainage network. Aerial photographs show a ~2.5 fold increase in drainage density between 1950 and 1992.		Alongside this change in vegetation cover, this area saw a marked increase in the presence of sandy gullies and ponds, which form an internal surface water drainage network. Aerial photographs show a ~2.5 fold increase in drainage density between 1950 and 1992.

	[[File:~~WaterPumpLungaLunga~~.~~jpeg~~\|thumb\| 400 px\| center\| Contemporary land use in Niger: millet farming and cattle herding. Figure source: [http://peoplefoodandnature.org/blog/global-landscape-restoration-the-art-of-the-do-able/ Landscapes for People, Food and Nature 2014]] / ICRISAT/M. Winslow on [https://www.flickr.com/photos/icrisat/ Flickr]]		[[File:MilletFarmingNiger.jpg\|thumb\| 400 px\| center\| Contemporary land use in Niger: millet farming and cattle herding. Figure source: [http://peoplefoodandnature.org/blog/global-landscape-restoration-the-art-of-the-do-able/ Landscapes for People, Food and Nature 2014] / ICRISAT/M. Winslow on [https://www.flickr.com/photos/icrisat/ Flickr] ]]



	===Local hydrogeology===		===Local hydrogeology===

Beod: /* Land cover changes and impacts on groundwater in southwest Niger */

2018-03-27T08:53:35Z

Land cover changes and impacts on groundwater in southwest Niger

← Older revision		Revision as of 09:53, 27 March 2018
Line 17:		Line 17:

	Alongside this change in vegetation cover, this area saw a marked increase in the presence of sandy gullies and ponds, which form an internal surface water drainage network. Aerial photographs show a ~2.5 fold increase in drainage density between 1950 and 1992.		Alongside this change in vegetation cover, this area saw a marked increase in the presence of sandy gullies and ponds, which form an internal surface water drainage network. Aerial photographs show a ~2.5 fold increase in drainage density between 1950 and 1992.

			[[File:WaterPumpLungaLunga.jpeg\|thumb\| 400 px\| center\| Contemporary land use in Niger: millet farming and cattle herding. Figure source: [http://peoplefoodandnature.org/blog/global-landscape-restoration-the-art-of-the-do-able/ Landscapes for People, Food and Nature 2014]] / ICRISAT/M. Winslow on [https://www.flickr.com/photos/icrisat/ Flickr]]