Metsi Consultants - DWA Home Page

More documents

Recommendations

Info

METSI CONSULTANTS: SUMMARY OF MAIN FINDINGS FOR PHASE 1 DEVELOPMENT Querying the Database to Determine the Biophysical Consequences of a Modified Flow Regime Step 13: Four modified flow regimes were created by combining the various flow reductions in different ways. Step 14: The volumes of water involved in each reduction of high flows or low flows were calculated and combined to give the overall volume required for each modified flow regime. Step 15: For each flow regime, the biophysical consequences of each reduction level were synthesized to create a description of the predicted river condition under that flow regime. Adding Severity Ratings to Predictions of Biophysical Change Step 16: The severity of each of the predicted consequences was expressed as a percentage. The less certainty of prediction the wider the percentage range. Within-year flood bands Range of water levels in wet-season lowflow Detail of riparian zones bedrock boulders Sedge section Moss section Aquatic zone Figure C.1. Illustration of wet-season and flood water levels marked on graphics of surveyed cross-sections. Wet Bank zone Lower Shrub zone Report No. 678-F-001 C-2 1:2 year Lower Dynamic zone Dry bank zone 1:20 year 1:10 year 1:5 year Upper Shrub or Tree zone Stable bank Back dynamic zone
METSI CONSULTANTS: SUMMARY OF MAIN FINDINGS FOR PHASE 1 DEVELOPMENT Table C.1 An example of the information contained in a consequence entry. Sev. = severity rating. % = equivalent percent reduction or increase in abundance or occurrence. For an explanation of severity rating see Section 4.2. Site Flow Aspect IFR 1 Wet-season low flows Reduction Level Compo nent Sub-component Result Sev. % Ecological Comment Social Comment Level 3 Fish Maluti Minnow Decrease 4 60-80% It is expected that the reduction of the Not commonly low flow wet period will have a major caught or utilised. impact on habitat quality and quantity. Red data species This change to the flow regime would significantly alter the prediction for this critically endangered species at this site, as spawning and migration cues, and availability and quality of spawning and incubation habitat would be reduced. Suitability (habitat criteria) of lateral habitats for refuge, foraging and passage of larvae and juveniles would also be reduced. Consequences would be evident in the form of changes in the abundance of larvae and juveniles and spawning success and hatching would be compromised. SOCIO-ECONOMIC COMPONENTS OF THE PROCESS Identifying the Social Impacts of Biophysical River Changes Step 17: The extent and nature of use of river resources by riparian people, and the present state of their health and that of their domestic stock, were described and quantified. The Population At Risk (PAR) was identified. Step 18: The predicted reductions in availability of the resources and services under any potential flow regime (Step 16) were used to rank the social impact for each resource and each health issue. Calculating the Economic Assessment of Compensation and Mitigation Step 19: An economic assessment was made of the current value of all river resources and services used by the PAR, using information from the detailed social survey. CALCULATING THE IMPACT ON THE SYSTEM YIELD Step 20: A yield analysis was performed using the volumes calculated in Step 14, to determine the impact of supplying a given flow regime to the downstream river on the yield. OUTPUTS OF THE DRIFT PROCESS The outputs consisted of the predicted consequences of four possible future flow regimes for the study rivers. These were referred to as IFR scenarios, and consisted of the following information. A modified flow regime for each part of each affected river. This is expressed in terms of: − low flows: seasonal upper and lower discharge ranges, and monthly averages for discharge and volume. − high flows:magnitude, duration and timing of flood events. Report No. 678-F-001 C-3
Page 1:
Kingdom of Lesotho Lesotho Highland
Page 4 and 5:
METSI CONSULTANTS: SUMMARY OF MAIN
Page 6 and 7:
Page 8 and 9:
Flow Scenarios METSI CONSULTANTS: S
Page 10 and 11:
Page 12 and 13:
Mitigation of Flow-Related Impacts
Page 14 and 15:
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Report No 678-F-001 METSI CONSULTAN
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
3.2.6 Detailed Sociological Study R
Page 38 and 39:
Page 40 and 41:
4.1.3 Design Limitation Report No 6
Page 42 and 43:
Negligible: 0% probability Minimal/
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
6.4. ECONOMIC IMPACTS Report No 678
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67: 8.2. BIOPHYSICAL CONSEQUENCES Repor
Page 68 and 69: Report No 678-F-001 METSI CONSULTAN
Page 76 and 77: 10.5. PUBLIC HEALTH IMPACTS Report
Page 88 and 89: 11.4.7 Animal Health Report No 678-
Page 90 and 91: 12.2.2 Social Reaches and Villages
Page 98 and 99: 13.2.9 Tanzania Report No 678-F-001
Page 102 and 103: Step 2: Optimisation of the preferr
Page 108 and 109: Chemistry (water quality) Botany Ma
Page 110 and 111: METSI CONSULTANTS: SUMMARY OF MAIN
Page 122: METSI CONSULTANTS: SUMMARY OF MAIN
show all

Metsi Consultants - DWA Home Page

Create successful ePaper yourself

Delete template?

Save as template?