技术

Keeping natural riparian vegetation and stabilizing riparian with gabions at Naro Moru River [肯尼亚]

technologies_1570 - 肯尼亚

完整性: 73%

1. 一般信息

1.2 参与该技术评估和文件编制的资源人员和机构的联系方式

关键资源人

SLM专业人员:
Cosmetic company:

Horsey John

Cinnabar Green Ltd.

肯尼亚

有助于对技术进行记录/评估的机构名称(如相关)
CDE Centre for Development and Environment (CDE Centre for Development and Environment) - 瑞士
有助于对技术进行记录/评估的机构名称(如相关)
Cinnabar Green Ltd. (CG) - 肯尼亚

1.3 关于使用通过WOCAT记录的数据的条件

编制者和关键资源人员接受有关使用通过WOCAT记录数据的条件。:

2. SLM技术的说明

2.1 技术简介

技术定义:

Structural riverbank protection by metal nets called gabion that are filled with stones

2.2 技术的详细说明

说明:

The studied land plot is situated in the semi-arid savannah zone of the Naro Moru sub-catchment at the foot of Mt. Kenya. A large-scale farmer owns a spacious land plot bordering Naro Moru River where he grows herbs and special plants to produce human care products. He rarely intervenes in the riparian area but is still interested in a good protection of water resources. Therefore, big stone control structures called gabions were installed to prevent big riparian trees from being undermined by water and destabilized by erosion. This method is cost intensive but can be applied locally for the protection of certain goods. The action was promoted by the Water Resource Users Association of the sub-catchment.

Purpose of the Technology: Despite semi-arid conditions, there is a high probability of flooding. Heavy rainfalls on upper slopes of Mt. Kenya lead to flood events in the semi-arid areas of Naro Moru River. These events have a destructive effect on the riverbanks, which have become instable by human induced activities such as overgrazing and deforestation. The instable riparian soils are eroded easily. The farmers lose their precious land and the water is polluted.

Establishment / maintenance activities and inputs: Big riparian trees are important for stabilizing the riverbed and riverbanks and for building a canopy that provides shade which enables the typical riparian conditions with its vast biodiversity. Thus, large metal nets (2x1x0.5 m) are filled with stones and placed in front of the roots to protect them from the direct current. These metal nets are called gabion and are placed at especially prone places. This structural measure contributes to mitigate or even stop riverbank degradation. High efforts are required to establish gabions. The costs for the metal net amount to 80 US-Dollar per net. Additionally, workforce must be found to fill the nets with stones from the river. Once installed, they ensure a good local protection. They are also used to protect bridge pillars. The life expectance of a gabion net is about 20 years if not destroyed by extreme events.

Natural / human environment: The plot is situated on a plateau at the western side of Mt. Kenya. There is not the same amount of precipitation as at the foot slopes of Mt. Kenya. However, the area still benefits from the runoff that is generated on the mountain. Precipitation in the so-called savannah zone ranges from 600mm to 900mm per year. Due to the high evaporation, rain-fed agriculture is only partly possible. Therefore most land users depend on irrigation using river water.
During the last decades, the region has experienced a still continuing population growth which increases population pressure in the area and removal and use of the vegetation along the rivers. The good accessibility and the moderate tourism allow even off-farm income-generation.

2.3 技术照片

2.5 已应用该技术的、本评估所涵盖的国家/地区/地点

国家:

肯尼亚

区域/州/省:

Kenya/Central Province

有关地点的进一步说明:

Nyeri/Naro Moru

具体说明该技术的分布:
  • 均匀地分布在一个区域
如果技术均匀分布在一个区域,则指定覆盖的区域(单位为平方千米):

2.15

如果不知道精确的区域,请注明大致覆盖的区域:
  • < 0.1 平方千米(10 公顷)
注释:

The riparian length as the crow flies is 2.15 km.

2.6 实施日期

如果不知道确切的年份,请说明大概的日期:
  • 不到10年前(最近)

2.7 技术介绍

详细说明该技术是如何引入的:
  • 在实验/研究期间
注释(项目类型等):

The WRUA talked to the farmer who introduced the technology

3. SLM技术的分类

3.1 该技术的主要目的

  • 降低灾害风险

3.2 应用该技术的当前土地利用类型

农田

农田

  • 一年一作
  • 乔木与灌木的种植
每年的生长季节数:
  • 2
具体说明:

Longest growing period in days: 60 Longest growing period from month to month: april to may Second longest growing period in days: 60 Second longest growing period from month to month: october to november

森林/林地

森林/林地

  • (半天然)天然森林/林地
(半天然)天然森林/林地:具体说明管理类型:
  • 非木材森林的利用
产品和服务:
  • 放牧/啃牧
  • 自然保持/保护
注释:

Major land use problems (compiler’s opinion): Due to the decreasing river flows, the riparian vegetation is being diminished.

Major land use problems (land users’ perception): Big riparian trees are threatened because of being undermined by water. The canopy and the roots of the trees are a vital component of the riparian habitat.

Other type of forest: Preservation

Forest products and services: grazing / browsing, nature conservation / protection

3.5 该技术所属的SLM组

  • 地表水管理(泉、河、湖、海)

3.6 包含该技术的可持续土地管理措施

结构措施

结构措施

  • S6:墙、障碍物、栅栏、围墙
管理措施

管理措施

  • M2:改变管理/强度级别
注释:

Main measures: structural measures

Secondary measures: management measures

3.7 该技术强调的主要土地退化类型

土壤水蚀

土壤水蚀

  • Wr:河岸侵蚀
生物性退化

生物性退化

  • Bh:栖息地丧失
  • Bs:质量和物种组成/多样性的下降
水质恶化

水质恶化

  • Hp:地表水水质下降
注释:

Main type of degradation addressed: Wr: riverbank erosion, Hp: decline of surface water quality

Secondary types of degradation addressed: Bh: loss of habitats, Bs: quality and species composition /diversity decline

Main causes of degradation: over abstraction / excessive withdrawal of water (for irrigation, industry, etc.), floods, population pressure

3.8 防止、减少或恢复土地退化

具体数量名该技术与土地退化有关的目标:
  • 防止土地退化
  • 减少土地退化
注释:

Secondary goals: mitigation / reduction of land degradation

4. 技术规范、实施活动、投入和成本

4.1 该技术的技术图纸

技术规范(与技术图纸相关):

In the Savannah zone large riparian trees are threatened, thus gabions are used to protect them and to sustain the canopy. The gabions are applied at the roots of the riparian trees to protect them from the erosive power of the stream.

Location: Irioko. Nyeri / Central Province

Technical knowledge required for field staff / advisors: high

Technical knowledge required for land users: low

Main technical functions: stabilisation of soil (eg by tree roots against land slides), stabilisation of riverbank

Secondary technical functions: sediment retention / trapping, sediment harvesting

Wall/ barrier
Depth of ditches/pits/dams (m): 1
Width of ditches/pits/dams (m): 1
Length of ditches/pits/dams (m): 2

Construction material (stone): Stones are collected directly in the riverbed.

Other type of management: The farmer protected his riparian zone with a fence.

作者:

Manuel Fischer

4.2 有关投入和成本计算的一般信息

具体说明成本和投入是如何计算的:
  • 每个技术单元
指定单位:

Gabion

指定单位面积(如相关):

2x1x0.5 m

其它/国家货币(具体说明):

Kenyan Shilling

如相关,注明美元与当地货币的汇率(例如1美元=79.9巴西雷亚尔):1美元=:

90.0

注明雇用劳工的每日平均工资成本:

2.70

4.3 技术建立活动

活动 时间(季度)
1. Installing and filling the metal wire with stones during dry season

4.4 技术建立所需要的费用和投入

对投入进行具体说明 单位 数量 单位成本 每项投入的总成本 土地使用者承担的成本%
劳动力 Installing and filling the metal wire with stones Persons/day 2.0 3.0 6.0 100.0
施工材料 Wire piece 1.0 80.0 80.0 100.0
技术建立所需总成本 86.0
技术建立总成本,美元 0.96

4.5 维护/经常性活动

活动 时间/频率
1. Control of the gabion nets
2. Control of fences

4.7 影响成本的最重要因素

描述影响成本的最决定性因素:

The price for the metal wire is the most cost determinant factor.

5. 自然和人文环境

5.1 气候

年降雨量
  • < 250毫米
  • 251-500毫米
  • 501-750毫米
  • 751-1,000毫米
  • 1,001-1,500毫米
  • 1,501-2,000毫米
  • 2,001-3,000毫米
  • 3,001-4,000毫米
  • > 4,000毫米
农业气候带
  • 半干旱

Thermal climate class: subtropics

5.2 地形

平均坡度:
  • 水平(0-2%)
  • 缓降(3-5%)
  • 平缓(6-10%)
  • 滚坡(11-15%)
  • 崎岖(16-30%)
  • 陡峭(31-60%)
  • 非常陡峭(>60%)
地形:
  • 高原/平原
  • 山脊
  • 山坡
  • 山地斜坡
  • 麓坡
  • 谷底
垂直分布带:
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.
关于地形的注释和进一步规范:

Altitudinal zone: 1870 m a.s.l.

5.3 土壤

平均土层深度:
  • 非常浅(0-20厘米)
  • 浅(21-50厘米)
  • 中等深度(51-80厘米)
  • 深(81-120厘米)
  • 非常深(> 120厘米)
土壤质地(表土):
  • 中粒(壤土、粉土)
表土有机质:
  • 中(1-3%)
如有可能,附上完整的土壤描述或具体说明可用的信息,例如土壤类型、土壤酸碱度、阳离子交换能力、氮、盐度等。:

Soil fertility is medium

Soil drainage / infiltration is medium

Soil water storage capacity is low

5.4 水资源可用性和质量

地下水位表:

< 5米

地表水的可用性:

水质(未处理):

不良饮用水(需要处理)

关于水质和水量的注释和进一步规范:

Availability of surface water: Just along the river, deeper ground water level 50-100m

5.5 生物多样性

物种多样性:

5.6 应用该技术的土地使用者的特征

生产系统的市场定位:
  • 商业/市场
非农收入:
  • > 收入的50%
相对财富水平:
  • 非常丰富
个人或集体:
  • 员工(公司、政府)
性别:
  • 女人
  • 男人
说明土地使用者的其他有关特征:

Land users applying the Technology are mainly Leaders / privileged

Population density: 200-500 persons/km2

1% of the land users are very rich and own 10% of the land.

Off-farm income specification: The land owner has a company that produces oils and herbs for care products. The company produces in a organic way and preserves the environment.

Market orientation of production system: Conservation/Preservation (But company produces care products for worldwide shipping)

5.7 应用该技术的土地使用者使用的平均土地面积

  • < 0.5 公顷
  • 0.5-1 公顷
  • 1-2 公顷
  • 2-5公顷
  • 5-15公顷
  • 15-50公顷
  • 50-100公顷
  • 100-500公顷
  • 500-1,000公顷
  • 1,000-10,000公顷
  • > 10,000公顷
这被认为是小规模、中规模还是大规模的(参照当地实际情况)?:
  • 大规模的
注释:

Average area of land owned or leased by land users applying the Technology: Also 15-50 ha for cropland

5.8 土地所有权、土地使用权和水使用权

土地所有权:
  • 公司
  • 个人,未命名
土地使用权:
  • 个人
用水权:
  • 自由进入(无组织)
  • 社区(有组织)
注释:

The land owner has a company that produces oils and herbs for care products. The company produces in a organic way and preserves the environment.

5.9 进入服务和基础设施的通道

健康:
  • 贫瘠
  • 适度的
教育:
  • 贫瘠
  • 适度的
技术援助:
  • 贫瘠
  • 适度的
就业(例如非农):
  • 贫瘠
  • 适度的
市场:
  • 贫瘠
  • 适度的
能源:
  • 贫瘠
  • 适度的
道路和交通:
  • 贫瘠
  • 适度的
饮用水和卫生设施:
  • 贫瘠
  • 适度的
金融服务:
  • 贫瘠
  • 适度的

6. 影响和结论性说明

6.1 该技术的现场影响

社会经济效应

生产

生产区域

降低
增加

社会文化影响

社区机构

削弱
加强
注释/具体说明:

This was not mentioned by the interviewee, but seems to be the case

SLM/土地退化知识

减少
改良

Livelihood and human well-being

reduced
improved
注释/具体说明:

The discussions about water conservation increase education. Also, the dialogue between farmers is improved.

生态影响

水循环/径流

水质

降低
增加

地表径流

增加
降低

地下水位/含水层

下降
补水
土壤

土壤水分

降低
增加
生物多样性:植被、动物

植物多样性

降低
增加

动物多样性

降低
增加
注释/具体说明:

monkeys

栖息地多样性

降低
增加
减少气候和灾害风险

洪水影响

增加
降低
其它生态影响

Riverbank degradation

improved
reduced

Preservation of canopy

reduced
improved

6.2 该技术的场外影响已经显现

旱季稳定可靠的水流

减少
增加

下游淤积

增加
降低

6.3 技术对渐变气候以及与气候相关的极端情况/灾害的暴露和敏感性(土地使用者认为的极端情况/灾害)

渐变气候

渐变气候
季节 增加或减少 该技术是如何应对的?
年温度 增加

气候有关的极端情况(灾害)

气象灾害
该技术是如何应对的?
局地暴雨
局地风暴
气候灾害
该技术是如何应对的?
干旱
水文灾害
该技术是如何应对的?
比较和缓的(河道)洪水

其他气候相关的后果

其他气候相关的后果
该技术是如何应对的?
缩短生长期

6.4 成本效益分析

技术收益与技术建立成本相比如何(从土地使用者的角度看)?
短期回报:

消极

长期回报:

稍微积极

技术收益与技术维护成本/经常性成本相比如何(从土地使用者的角度看)?
短期回报:

中性/平衡

长期回报:

积极

注释:

The establishment costs are quite high.

6.5 技术采用

  • 单例/实验
如若可行,进行量化(住户数量和/或覆盖面积):

1 landowner

在所有采用这项技术的人当中,有多少人是自发的,即未获得任何物质奖励/付款?:
  • 91-100%
注释:

100% of land user families have adopted the Technology without any external material support

There is no trend towards spontaneous adoption of the Technology

Comments on adoption trend: The costs are too high for an average farmer to adopt the technology.

6.7 该技术的优点/长处/机会

土地使用者眼中的长处/优势/机会
Ensuring an intact environment to guarantee the organic origin of the company products.

How can they be sustained / enhanced? Control that the riparian area is not being polluted or destroyed.
编制者或其他关键资源人员认为的长处/优势/机会
Conservation of the unique riparian habitat

How can they be sustained / enhanced? Continue the protective measures and hinder negative intervention in the riparian area.
Through the environmental activities, the acceptance of the company increases.

How can they be sustained / enhanced? Regular interaction improve neighborly relations.

6.8 技术的弱点/缺点/风险及其克服方法

编制者或其他关键资源人员认为的弱点/缺点/风险 如何克服它们?
The implementation of the gabions is very cost-intensive. Alternatives should be checked out.
The origin of the vegetation decline, the decreasing river flow, is not being combatted. Water abstractions in the upper reaches should be diminished.

7. 参考和链接

7.1 信息的方法/来源

模块