E1778 Tanzania Energy Development and Access Project v3 (TEDAP) P092154 Public Disclosure Authorized Environmental Assessment – Annex 2: Geological Public Disclosure Authorized Investigations (EA) Part A (January 2005) Public Disclosure Authorized Public Disclosure Authorized E w 7 ,~~~1.4 .# t REINFORCEMENT AND UPGRADING OF DSM, KILIMANJARO AND ARUSHA TRANSMISSION UNES AND DISTRIBUTION SYSTEM PROJECT: Environmental Studies ANNEX 2: Geological Investigations Leonard B. Kassana Research & Development Department, Tanzania ElectricSupply Company Limited, P.O. Box 9024, Dar es Salaam. Tanzania. January 2005 I Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro And Arusha Transmission Lines ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL INVESTIGATIONS LIST OF TABLES Table 1: Grain Size Distribution Table 2: Average PH levels Soil Properties LIST OF APPENDICES Appendix 6.1: Maps Appendix 6.2: Test pits logs Appendix 6.3: Laboratory Results Appendix 6.4: Photo Records of the Investigation Area Appendix 6.5: Other relevant literature and correspondence docs ACRONYMS AND ABBREVIATIONS CH Inorganic clays of high plasticity kv Kilo Volt MA Moshi-Arusha ND Non-Dispersive QDS Quarter Degree Sheet pH Negative decinal logarithm of the hydrogen ion activity Pi Plasticity Index TANESCO Tanzania Electric Supply Comnpany Limited Km Kilometers SM Silty sands and sand-clay rnixtures ToR Terms of Reference TP Test Pit USCS Unified Soil Classification System (American Society for Testing and Materials, 1985). Leonard B. Kassana iii Tanzania Electric Supply Company Limited 1/26/2005 And Arusha Transmission Lines Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro INVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL ACKNOWLEDGEMENT for the assistance in one-way or the other. Their The author is highly indebted to the following people helpful in carrying out this task: logistical support and comments as well, have been Dar es Salaam: Director Corporate Planning & Research * Mr. K.R. Abdulla - Tanesco, Manager Research & Development * Mr. D.E.P. Ngula - Tanesco, Chief Research & Investigation Engineer * Mr. M. Katyega - Tanesco, Senior Geologist * Mr. K. Kabaka - Tanesco, Environmental Engineers * Messrs Mansur, H & Lazimah, J - Tanesco Arusha: Regional Manager * Mr. C.J. Masasi - Tanesco Civil Engineer Technician, Transmission Lines * Mrs. Dina Msuya - Tanesco iv Leonard B. Kassana 1/26/2005 Tanzania Electnc Supply Company Limited Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro And Arusha Transmission Lines ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL INVESTIGATIONS EXECUTIVE SUMMARY This document is an annex to the main report for Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro And Arusha Transmission Lines ENVIRONMENTAL STUDIES. It deals pertaining Geology with issues and in particular soil conditions and its main objective general overview is to obtain of the geological/soil conditions of the project areas. * Ihe proposed corridors for the Moshi - Arusha 132 kV overhead transmission is approximatejy 70 km long and the Dar es Salaam transmnission routes are approximately 43 km long. Regionally, the Moshi - Arusha area lies within the Great Eastern African Rift dominated by volcanic formations. Valley and is The transmission corridor traverses east west lower flat lying foot of through southern the mounts Kilimanjaro and Meru. The proposed transmission was selected to run parallel with corridor the existing 132 kV transmission line from Moshi Kiyungi substation to Arusha Njiro substation. * The Moshi - Arusha transmission towers will be founded in volcanic of Sandy Silty sediments mainly consisting CLAY and few places have soils mainly composed of Sandy * Soil samples SILT/Silty SAND. taken from Moshi - Arusha Transmission line corridor varying, a bit have pH values slightly on the acidic side and largely on the alkaline side. About samples have 80% of the tested soil PH values greater than 7.0 indicating that the soils are of the tested alkaline in nature. Only 20 % soil samples show acidic nature. By these results, the ground - Arusha Transmission conditions in the Moshi line route are not acidic and therefore it may be a very less corrosive inferred that the site pose threat to the transmission towers. During the fieldwork, inspection was conducted random visual on the existing 132 kV transmission towers and corrosive not observed on the towers. effects were * The Dar Transmissions corridors are located in the coastal plain environment dominated by superficial sands of the flat, low lying coastal plain represented from by redistributed outwash material the fault blocks. River alluviums consisting of sands varying are from off-white to buff-brown also found in the corridors. Test on soil pH for the samples that collected from Dar corridors show the soils specimen are acidic, but the number of soil conclusion. samples is too small to make a definitive * Due to terrain nature of the transmission corridors and non-dispersive nature of the few samnples taken from the sites, it is apparently inferred that soil erosion along the transmission is not severe. Control measures for soil erosion will have to be determined design/construction on a tower-to-tower case during the phase. At this stage of this report we may not have a suitable * Due to the preliminary blanket solution. nature and time/budget constraints of the study, measurement for the Field Resistivity assessing electrical conductivity of the ground, was period and thus not conducted during this it is recommended to be done at later phase of the study/implementation. Leonard B. KIassana v Tanzania Electnc Supply Company Limited 1/2&62005 And Arusha Transmission Lines Reinforcement & Upgrading of Dar es Salaam, Kilimanjaro INVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL 1. INTRODUCTION of Kilimanjaro-Arusha Transmission Lines and The field investigations for Reinforcement & Upgrading weeks no. 49 and 52 of 2004. This Dar es Salaam transmission lines took place between respect to geological/soil conditions of report gives an account of preliminary findings with the project area. Tanzania for Moshi-Arusha and Dar es project areas are situated in Northern and Eastern parts of The Transrnission Corridor lies between 30 Transmission routes respectively. The Moshi-Arusha Salaam The Dar es Salaam transrmission and 30 26' S Latitudes, 36°41'E and 370 19'E Longitudes. 22' S 6°43' and 6°56'S latitudes and 39°10' corridors lie between the following geographical coordinates: areas are shown in Figure 1. and 39021 'E longitudes. General locations of the project ~- ^^,, Lake R *Nawasha 0 150 km rr-ftw*a oLaa uru s \ Mimlagqwi R N Wbere R. -Tbora. *Songidao __ .Tanzania -- Wm1ilmR R-ib * Mpsd KJiQgo-R Tahg~nkaKIIOSO * Ruvu . G,u RBuah raF iIr. vA Sumb(wng R u . ftfakra. ;k--Mibmbe, HL"o.A * PiorectAre.s 1o, LaKe Zambiea1 BEangweLIu X. 0i Malwr @i'g7 MAGELLAN GeographixRI Mozarbiquev (805) 685-3100 www.maps.corn94 _ Figure 1: General location of the Project Area 1/26/2005 Leonard B. Kassana Page 1 of 8 Tanzania Electric Supply Company Limited Reinforcement & Upgrading of Dar es Salaam, ENVIRONMENTAL Kilimanjaro And Arusha Transmission Lines STUDIES- ANNEX 2: GEOLOGICAL INVESTIGATIONS 1.1 Scope of Work The scope of the assignment was to obtain general overview condition of the soil and general geological of the area so as to highlight preliminary Environmental effects of soil erosion with respect to Impact Assessment. Specifically, the scope included: * Scan and traverse along the proposed corridor documenting rock and soil Overview Mapping. types in general i.e. * Zoning and documenting different geomorphologic conditions along the proposed * Spot soil investigations corridor at few selected sites at locations to geologist. be determined at the site by the 1.2 Methods of Investigations Senior Geologist, Mr. Leonard B. Kassana of Research and Development Head Office, executed Department, TANESCO all investigations in accordance to the ToR. The field light investigations consisted of: * Carrying out soil investigations within the selected transmission samples corridors by test pitting. Soil were collected for laboratory analysis as well * Ground water measurements in the Investigation pits. * Overview Geological Mapping * Literature search relevant to the project. An overview mapping was based on: * Interpretation of topographic map at 1:50,000 and 1:100,000 scales * Interpretation of Geological maps, Quarter Degree Sheet (QDS) at a * Walkover scale 1:125,000 survey along the proposed transmission corridors Refer to Appendix 6.1 for maps locating investigation areas. 2. TOPOGRAPHY, REGIONAL GEOLOGY AND SITE GEOLOGICAL CONDITIONS 2.1 Kilimanjaro - Arusha Region 2.1.1 Topography The project area is dominantly covered by volcanic mountain massifs country at about 900 rising abruptly from plateau m.a.s.l For Arusha areas, mount Meru raises summit of about from about 900 m.a.s.l to the 4600 m.a.s.l. and Kilimanjaro rises from about 5895 m.a.s.l. 900 m.a.s.l to the highest peak of In general, the proposed transmission line runs parallel to both existing Transmission line 132 KV Moshi - Arusha and the main Moshi - Arusha road. The line of the runs almost east west direction south high volcanic mountains in Africa, namely Kilimanjaro running and Meru. The transmission lines parallel to the Moshi-Arusha road in are the south of the mountains. North of this road, terrain is of mounded topography formed the by Meru lahars while in the south of the road our transmission proposal is running, and where outwashes from the lahars form a more even plain. Wide spread topographical features are formed by the spread of 'lahars' or cold mudflow south and southwest of mount Kilimanjaro in the emanating from Kibo peak and mount Meru. For the further details of the topography the reader is kindly referred to the #42, 56 & 57 and QDS #55. special QDS covering Leonatd S. Kassana Tanzania Electnc Supply Company Limited Page 2 of 8 112612005 Transmission Lines & Upgrading of Dar es Salaam, Kilimanjaro And Arusha Reinforcement INVESTIGATIONS ENVIRONMENTAL STUDIES - ANNEX 2: GEOLOGICAL 2.1.2 Regional Geology of Pleistocene to Recent. According to and Kilimanjaro are younger volcano products Mt.