Physical and Topographic features
The highest altitude of the county is 5,200m in Chuka/Igambang’ombe and Maara while the lowest is 600m Eastwards in Tharaka.
The main physical feature of the county is the 360 Km2of Mt. Kenya forest distributed between Maara and Chuka/Igambang’ombe constituencies.
The forest serves as a tourist attraction, catchment area for Tana River, a source of fuel wood, fodder and honey for the communities living around it.
Major hills found in the county landscape include Kiera, Munuguni and Njuguni in Maara constituency and Kijege and Ntugi in Tharaka constituency. The hilly terrain of the County leads to soil erosion hence environment degradation.
The terrain also makes construction and maintenance of road networks costly.
The topography of Chuka/Igambang’ombe and Maara constituencies is greatly influenced by the Mt. Kenya volcanic activity creating ‘V’ shaped valleys within which the main tributaries of River Tana flow originating from Mt. Kenya forest.
The tributaries flowing eastwards are: Thuci, Mara, Nithi, Mutonga, Naka, and Ruguti. Tharaka on the other hand is traversedby several rivers, which originate from both the Mt. Kenya and Nyambene Hills, flowing eastwards as tributaries of Tana River. These include Mutonga, Thingithu, Kathita, Thanantu, Thangatha, Kithinu and Ura rivers which provide water for irrigation in the moderately densely populated locations in parts of Tharaka. The region comprises of low, hilly, stony and sandy marginal lowlands with moderate forest cover.
The County has two main ecological zones. The highlands (upper zone) comprise of Maara and Chuka which receive adequate rainfall for agriculture.
The semi-arid (lower zone) covers Tharaka and receives less rainfall suitable for livestock production. Poor methods of farming and soil conservation, charcoal burning and overgrazing have left the earth bare and rocky.
The sloping areas have experienced uncontrolled soil erosion, which has resulted in deep gullies across the landscape especially in Tharaka. The drainage pattern consists of rivers and streams that ultimately drain into the Indian Ocean through Tana River.
Temperatures in the highland areas range between 140C to 300C while those of the lowland area range between 220C to 360C.
Tharaka constituency, which lies in the lower side, experiences temperatures of up to 40oC at certain periods.
The county has a bi-modal rainfall pattern with the long rains falling during the months of April to June and the short rains in October to December.
The rainfall ranges from 2,200mm in Chogoria forest to 500mm in Tharaka. The high altitude areas experience reliable rainfall while middle areas of the county receive moderate rainfall. The lower regions receive low, unreliable and poorly distributed rainfall.
The climate of the county is favourable for cultivation of tea, coffee, maize, cowpeas, pigeon peas, sorghum, millet, green grams, tobacco and a variety of other food crops.
However, there are unusual climate variability incidences arising from climatic change.