APPENDIX III
Water Quality Characteristics of Some Iranian Streams and Lakes

Caspian Sea Area

Table 1 shows the results of analyses of a number of streams flowing from the Alborz mountains into the Caspian Sea.

The waters of most of Caspian streams fall in the moderately hard to relatively hard categories. In many cases the calcium-magnesium hardness was close to 200 mg/l.

Hard waters are more productive of aquatic life than soft waters. When stones in the streams were examined, mayfly nymphs, stonefly nymphs, and a few caddisfly larvae seemed to be everywhere conditions were favorable for them, even in quite silty waters such as the Shahrud. Futhermore these waters should conduct electricity well, making it possible to shock fish for fish samples without placing salt blocks in the streams above sampling points.

Tabriz Area

Table 2 shows the results of water analyses in the Tabriz area where there was greater variation in the hardness of the streams than in any other area visited. Many streams had waters that were in the relatively hard category. The hardest water sampled (820 mg/l) was found in the Talkheh Rud which drains areas with salty soils. It finally reaches Lake Rezaiyeh, a very large salt water lake. The softest water sampled was that of the Basmenj Chay (70 mg/l) which flows down from Kuh-e-Sahand, a mountain of 12,000 ft southeast of Tabriz. The Aghlaghan Chay a beautiful stream flowing from the southern slopes of Savilan mountain had a calcium-magnesium hardness of only 100 mg/l at Nir while the Khiav Chay (Darreh Rud) on the north slope of Savilan mountain was among the softest and coldest waters sampled (calcium-magnesium hardness 80 mg/l, temperature 7.5°C).

Two lakes in the Tabriz area with unusual water quality characteristics were visited. Lake Ghoohrygol with a calcium-magnesium hardness of 140 mg/l, had a total alkalinity of 350 mg/l, and conductivity of 2,500 micromhos. The chloride content of this lake which has no outlet was 74 mg/l. Total dissolved solids amounted to 594 mg/l, on 6 November 1968.

Lake Shurabel at Ardebil proved to be saltier than sea water with a total chloride content of 24,800 mg/l, conductivity of 60,000 micromhos, and total dissolved solids content of 80,000 mg/l.

Vladykov (1964) has already described the chemical nature of Lake Rezaiyeh water which is several times saltier than sea water.

Isfahan Area

The principal stream in the Isfahan area, the Zayandeh Rud, was sampled at the Shah Abbas Dam site and at Pol Kalleh. At both points the water showed the same total alkalinity and calcium-magnesium hardness: respectively, 160 mg/l and 180 mg/l or “moderately hard” water. The stream had cold water at both points.

Table 3 gives the results of water analyses made in the Isfahan area. The only other waters sampled were streams originating from ghanats. One of these near Shahr Kord had a calcium-magnesium hardness of 160 mg/l and the other near Golab had a hardness of 180 mg/l, indicating that probably all waters in this area are moderately hard.

Table 1

Results of Analyses of Streams and Reservoirs in the Caspian Sea Area

TABLE 2

Results of Water Analyses of Streams and Lakes in the Tabriz Area

¹ Total dissolved solids 596 mg/l; chlorides 74 mg/l; conductivity 2,500 micromhos

² Total dissolved solids 80,000 mg/l; chlorides 24,800; conductivity 60,000 micromhos

Although the area lacks streams other than the Zayandeh Rud, the potential for fish ponds in this area, because of new irrigation canal plans and development, is greater than any other area visited.

Shiraz Area

The results of water analyses of streams and springs in the Shiraz area are given in Table 4.

The most important stream from the standpoint of fish culture in the area is the Kur River which has relatively hard water at 210 mg/l.

The fine large springs at Dashg-Arjan and Chehelcheshmeh have relatively hard waters with favorable temperatures for rearing trout. Since both are bubbling springs, their waters will require mechanical aeration before use in trout culture to remove excess carbon dioxide and nitrogen.

The Quareh Aghaj and upper Kur River have been recommended for stocking with rainbow trout by Nümann and Hosseinzadeh (1968). They have also recommended rainbow trout stocking in the Lighvan Chay and Karun Rivers. Souf have also been recommended for stocking in the Kur and Zayandeh Rud Rivers.

The stocking of a carnivorous fish, such as the Souf in the same waters with trout (except in “two-story” reservoirs) is not considered good management.

Table 3

Results of Water Analyses of Streams in the Isfahan Area

TABLE 4

Results of Water Analyses of Streams in the Shiraz Area