Within the district, Cherthala, Ambalappuzha, Kuttanad and Karthikappally lie completely in the low land region. There is no forest area in the district, and any mountains or hills either except for some scattered hillocks lying between the Bharanikkavu and Chngannur blocks in the eastern portion of the district.
Alappuzha has a flat, unbroken sea coast of 82 Km length which is 13.9 percent of the total coastal line of the state. An interesting phenomenon of this seacoast during the month of June is the periodic shifting of mud bank popularly known as "Chakara" within a range of 25 Km in Alappuzha-Purakkad coast due to hydraulic pressure when the level of backwater rises during south-west monsoon. The climate in the district is moist and hot in the coast and slightly cool and dry in the interior parts of the district. The average monthly temperature is 25 degree Celsius. The district also gets the benefit of two outstanding monsoons as in the case of other parts of the state. The hottest month is from March to May. The South-west monsoon is prevalent between the months of June to September, and the North-east monsoon between the months of October to November. The average rainfall in the district is 2763 mm.
The two most important minerals which occur in large quantities in the district are glass and foundry sand. Lime shell is exploited commercially. High quality sand deposits occur between Alappuzha and Cherthala which form a stretch of 35 Km in length along the western side of Vembanad Lake. Large quantities of sand are being mined at Pallipuram for manufacturing sand lime bricks. Vast deposits of lime shell occur in Vembanad Lake covering an area of 15 Sq.Km. up to a depth of 8 metres between Pathiramanal and Vaikom. China clay and ordinary clay occur in various places and are used as building materials. The raw material required for granite carving is obtained from Chengannur.
The district has a network of rivers, canals and backwaters. Manimala, Pampa and Achancovil are the major rivers. The Manimala River originates from Mothavara hills in Kottayam district enters the district at Thalavadi village in Kuttanad taluk and passes through Edathua and Champakulam villages and joins the Pamba River at Muttar. It has a length of 91.73 Km and drainage area of 802.90 Km. Achankovil River, often known as Kulallada river, originates from Pasukida mettu, Ramakkal Theri and Rishimalai of Kollam district enters the district at Venmony and has a catchment area of 1155.14 Sq.Kms and a marginable length of 32.19 Km. It passes through Cheriyanad, Puliyoor and Chengannur villages, enters Mavelikkara Taluk at Chennithala, flows through Thriperumthura and pallippad villages and joins Pamba at Veeyapuram. Pamba, the third longest river in Kerala is formed by several streams originating from Peerumedu plateau in Idukki district. It enters Alappuzha district at Chengannur and flows through Pandanad, Veeyapuram, Thakazhy, and Champakulam through a distance about 177.08 Km and plunges into vembanad lake through several branches. The river has a length of 117 Km and is navigable to a length of 73 Km. The catchment area of this river is 1987.17 Sq.Km. The main tributaries of the river are Pambayar, Kakki Ar, Arudai Ar, kakkad Ar and Kallar.
The Vembanad Lake, the most important of the west coast canal system has a length of 84 Km and an average breadth of 3.1 Km. It covers an area of 204 Sq.Kms. stretching from Alappuzha to Kochi. Pamba, Achankovil, Manimala, Meenachil and Muvattupuzha rivers flow into this lake. Pathiramanal, often called the mysterious sand of midnight, resplendent with coconut palms and luxuriant vegetation, is situated in the centre of this lake. Perumbalam and Pallippuram are the other islands in this lake. The Thannermukkom regulator constructed across Vembanad Lake between Thannermukkom and Vechur is intended to prevent tidal action and intrusion of saline water into the lake. It is the largest mud regulator in India. Stretching between Panmana and Karthikappally, Kayamkulam Lake is a shallow lake which has an outlet to sea at Kayamkulam barrage. It has an area of 59.57 Sq.Km., a length of 30.5 Km and an average breadth of 2.4 Km. It connects Ashtamudi lake by the Chavara Panmana canal.
Alappuzha has a network of canals included in the west coast canal system which are used for navigation. The important canals are Vadai canal, commercial canals and the link canals between these two canals. Apart from these, there are many inland canals which are mainly used for passenger navigation and commercial purposes. The lakes are used for inland water transport of passengers and cargo. Inland fisheries have also been flourished in these regions.