Wadi Houran is one of the largest valleys in Iraq. Although it is discharging billions of rainfall water over/during many years to Euphrates river, it's almost devoid of agricultural investment. The current study aims to focus on this important valley water resource and study the possibility of constructing a series of small dams to store rainfall water and planting forestry and establishing a natural reserve that is able to sustain and improve ecology system. Target area of 4000 km2 is selected in the midstream of the valley. In general, it is about one billion m3 of rainwater flowing to Euphrates River during some years with yearly average values about 400 Mm3. Four dams were constructed to store about 46 Mm3 of rainwater. It is possible to construct small-dam-series of optimal height and location to expand the rainwater harvesting and groundwater recharging. A Current study was done and aimed to establish of oases and natural reserves in order to improve climate conditions, minimize the dust and CO2, mitigation of summer high temperature and decrease the soil erosion due to torrents. This study recommended constructing 13 optimal height dams that store about 303 Mm3 of water, and increase the water surface area of reservoirs in this valley from 15 to 90 km2which leads increase the water volume that is recharging ground water from 4.7 Mm3 to 28 Mm3 per year.
Surface infiltration plays an important role in watershed management and flood forecasting; Furthermore increase the efficiency of irrigation system and reduce water losses during the irrigation process. Experiments carried out on the Wadi AL-Ratga of the western desert, Iraq during 2019; which had been selected as a study area. The infiltration rate data were collected using double ring infiltrometer at selected ten points of the selected study area. The duration of double ring test ranged between 30 minutes to one hour based on the infiltration speed in the soil, about 6 to 12 readings were recorded for the infiltration rate at each points. The aim of this paper is to check the ability of the common infiltration models such as Horton’s, Kostikov’s and Philip’s to accurate estimated infiltration rate. These models were fitted to the observed infiltration data for estimation of models parameters and to find appropriate model for this region. Horton’s infiltration model’s parameters such as infiltration decay constants ’k’ And the value of infiltration capacity at onset of infiltration (fo) had been calculated in the ranges of 3.38-6.97 hr-1 and 21 to 47.8 cm.hr-1; respectively; for all the ten points. Philip’s infiltration model’s parameters such as the values of conductivity constant ‘A’ and sorptivity ’S’ were obtained in the ranges of 3.48-12.49 cm.hr-1 and 9.96 to 17.2 cm/hr0.5; respectively. Similarly; the Kostikov’s model’s parameters ‘a’ and ‘b’ were obtained in the range of 8.85-24.38 and 0.732-0.829; respectively. Based on results of infiltration models at the selected points the predicated parameters have realistic capability predication. The results showed that all models provided the acceptable values for Root Mean Square Error (RMSE) as1.45, 2.01, 1.88 cm.hr-1 for Horton’s, Kostikov’s and Philip’s model; respectively; The highest model efficiency (ME) as 99% for all models; and the maximum Relative Error (RE) values as 16% at all points except point 2 was calculated as 21%. This indicated that infiltration can be well-described by the Horton’s model little more than other models at the study area.