
| Irrigation Reference Manual (Peace Corps, 1994) |
| Chapter 2 - Physical and biological resource base |
![]() | 2.5 Conducting initial environmental evaluations of irrigation projects |
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The following illustrative form provides a scheme that can be used by Volunteers or technicians to identify and rank probable environmental impacts from proposed field work prior to the initiation of construction or development activities. The form can also be used to help identify mitigative measures that will eliminate these environmental impacts. Impacts are identified as to whether they are of MINOR, MODERATE, OR SIGNIFICANT environmental concern. Any MODERATE impact should identify measures that can improve the scheme. Any SIGNIFICANT impacts should identify alternative activities that can replace the initial proposed project.
PART I PROJECT CHARACTERIZATION
Project Description
_______________
_______________
1. Obtain topographic map(s) covering the area within or including the proposed project development scheme.
2. Delineate the watersheds, natural drainage directions, and approximate affected area within which the project will occur. Affected area includes lands directly upstream and downstream from the proposed project, which the project could alter by changing runoff or flood flows, vegetation cover, or soil conditions.
3. Obtain land use, vegetation, soils, or flood maps for the affected area if available.
4. Obtain information on the likelihood of occurrence of important wildlife, fisheries, or habitat types, and the presence of threatened or endangered species in the affected area.
5. Obtain information on the likelihood of occurrence of important cultural resources in the affected area.
Note: Bring the topographic map to the field when doing the field review.
PART II FIELD EVALUATION
Based on available information and field observations, evaluate the predicted effect of the proposed project on the following resources. Include proposed mitigation resources, if necessary.
|
N |
NO environmental impact or IMPROVED environmental
conditions. |
|
L |
MINOR negative environmental impact. |
|
M |
MODERATE negative environmental impact. |
|
S |
SIGNIFICANT negative environmental impact. |
|
U |
UNKNOWN environmental impact. |
I Water Resources
Use the topographic map to make a brief sketch of the proposed development scheme. Identify significant local features, including rivers, canals, ponds, lakes, forest lands, wetlands, other unique habitats, and archeological sites. Show the apparent flow directions for floods and note any obvious signs of flood depths or flood locations for a 10-year flood. Include a map scale.
1. The project is located in a floodplain area. (Yes) (No)2. The project will increase/decrease/have no effect on the duration of floods (circle one answer). If yes, the ranking of impact is ________ .
3. The project will change the location of floods. (Yes) (No) If yes, the ranking of impact is _______ .
4. The project will change stream channel shapes, or the amount or type of vegetation alongside streams. (Yes) (No)
Impact Ranking
|
MINOR |
MODERATE |
SIGNIFICANT |
|
Some change, but overall channel/vegetation remains the
same. |
Causes measurable change in shape or vegetation. |
Causes major change in channel shape or
vegetation. |
5. Recommended measures to mitigate (reduce) effects: _________ .6. Explain how recommended measures will mitigate moderate or significant impacts.
7. What moderate or significant impacts cannot be mitigated and why?
II Fish and Wildlife
1. Project will result in destruction or degradation of habitat for fish or wildlife. (Yes) (No) If yes, the ranking of this impact is ________ .2. Project will block fish or wildlife migratory pathways. (Yes) (No) If yes, the ranking of the impact is ________ .
Impact Ranking
|
MINOR |
MODERATE |
SIGNIFICANT |
|
Impacts localized and no impacts to migratory pathways or
habitat. |
May temporarily block pathways or eliminate habitat. |
Will block migratory pathways or will eliminate
habitat. |
3. Endangered or threatened species are likely to occur in the project area. (Yes) (No) If yes, list.4. Proposed project will result in loss of individual threatened or endangered species. (Yes) (No) If yes, which one(s) and how?
5. Will any loss of habitat affect the survival of species? Explain.
6. Recommended measures to mitigate effects: ________ .
7. Explain how recommended measures will mitigate moderate or significant impacts.
8. What moderate or significant impacts cannot be mitigated and why?
III Vegetation
1. Vegetation types found in the area include _______ .2. Project will result in cutting of trees, or loss of vegetative cover. (Yes) (No) The ranking of the impact is _______ .
Impact Ranking
|
MINOR |
MODERATE |
SIGNIFICANT |
|
No loss of important plant communities or changes in
runoff. |
Some loss of important plants and change in runoff
patterns. |
More than 50 percent of plant cover lost and runoff patterns vary
greatly. |
3. Recommended measures to mitigate effects: ________ .4. Explain how recommended measures will mitigate moderate or significant impacts.
5. What moderate or significant impacts cannot be mitigated and why?
IV Soils
1. Changes in soil moisture:(a) waterlogging ________ .
(b) drought ________ .2. Project will cause soil loss from farm fields. (Yes) (No) If yes, ranking is ______.
3. Project will result in adverse changes to soil physical or chemical conditions. (Yes) (No) If yes, ranking is ________ .
Impact Ranking
|
MINOR |
MODERATE |
SIGNIFICANT |
|
Soil loss less than 5 tons/ha/year, and no salt or chemical
concentration. |
Soil loss greater than 5 tons/ha/year, and some salt or chemical
concentration. |
Soil loss greater 10 tons/ha/year, and high salt or chemical
concentration. |
4. Recommended measures to mitigate effects: ________ .5. Explain how recommended measures will mitigate moderate or significant impacts.
6. What moderate or significant impacts cannot be mitigated and why?
V Cultural Resources
1. Proposed project will result in the loss of archeological, historical or cultural resources. (Yes) (No) If yes, identify resources and rank the impact.
Impact Ranking
|
MINOR |
MODERATE |
SIGNIFICANT |
|
Project will make cultural resource less accessible. |
Project will result in loss or damage to less important
resources. |
Project will result in the loss or damage of important
resources. |
2. Recommended measures to mitigate effects: ________ .3. Explain how recommended measures will mitigate moderate or significant impacts.
4. What moderate or significant impacts cannot be mitigated and why?
VI Summary of Moderate and Significant Impacts and Recommended Mitigative Measures ________ .