تنها از آب چشمه‌های کوچک زیرزمینی موجود در بستر دریاچه تغذیه می‌شود و بخش ناچیزی از آن هنگام بارندگی تأمین می‌شود اما به صورت سطحی و خیلی کم. عمیق‌ترین بخش آن هفت متر با دمای آب بیست و سه  درجه سانتیگراد و میدان دید در زیر آب کمتر از یک متر می‌باشد که در جنوب شرقی آن واقع شده‌است  بستر دریاچه مملو از لجن و رسوبات ته‌نشین شده می‌باشد که حالت چسبندگی بسیاری دارد. از سرریز آب دریاچه نیز رود کوچکی تشکیل می‌شود که آب آن مورد استفاده کشاورزان روستاهای کوشک و آیین است. در تابستان این دریاچه محل ماهی‌گیری، آب‌تنی و قایق‌رانی و در پاییز، مأمن پرندگان مهاجر مانند قو، غاز، مرغابی و در زمستان با توجه به برودت هوا و یخ زدن سطح آن قابل اسکی سواری است

 The beautiful Lake Evan is located in the northern half of Alamut, on the slopes of the Khashchal Mountain, within a distance of seventy-five kilometers from Qazvin and among the four villages of Evan, Verben, Zwardasht and Zarabad, Qazvin.The beautiful Lake Evan is located in the northern half of Alamut, on the slopes of the Khashchal Mountain, within a distance of seventy-five kilometers from Qazvin and among the four villages of Evan, Verben, Zwardasht and Zarabad, Qazvin.
The lake, which covers more than seventy thousand square meters, is located at an altitude of 1,800 feet 15 meters above sea level. Its length is at the longest part of the thirty-twenty-five meters and its width is two hundred and seventy five meters.
Only the smallest springs of the underground lake are fed on the lake bed, and a small part of it is fed from the rain but rather superficially. The deepest part is seven meters with water temperature of twenty three degrees Celsius and underwater water field is less than one meter in the southeast. The bed of the lake is filled with sludge and sedimentary deposits, which has a lot of adhesion. There is also a small stream of water from the lake's water, which is used by the farmers in the villages of Kashk and Ayin. In the summer, the lake is a fishing, paddling and sailing place, and in the autumn, is hired by migratory birds such as swans, geese, ducks, and in winter it is skiing with air cooling and freezing.