var par = Expression.Parameter(typeof(water_flow1), "current");
            var cloneExpression = Expression.MemberInit(
                    Expression.New(typeof(water_flow1)),
                    Enumerable.Range(0, typeof(water_flow1).GetProperties().Length - 1).Select(i =>
                    Expression.Bind(
                    typeof(water_flow1).GetProperties()[i],
                    Expression.Property(par, typeof(water_flow1).GetProperties()[i])
                    )
                ).ToArray()
            );
            var cloneFunc = Expression.Lambda<Func<water_flow1, water_flow1>>(cloneExpression, "Clone", new[] { par }).Compile();

public static TOut Copy<TIn, TOut>(TIn source) where TOut : new()
    {
        ParameterExpression parameterExpression = Expression.Parameter(typeof(TIn), "source");
        MemberInitExpression memberInitExpression = Expression.MemberInit(
            Expression.New(typeof(TOut)),
            (from property in typeof(TOut).GetProperties()
             where property.CanWrite
             from sourceProperty in typeof(TIn).GetProperties()
             where sourceProperty.Name == property.Name && sourceProperty.PropertyType == property.PropertyType
             select Expression.Bind(property, Expression.Property(parameterExpression, sourceProperty))).ToArray()
        );

        Expression<Func<TIn, TOut>> lambda = Expression.Lambda<Func<TIn, TOut>>(memberInitExpression, parameterExpression);
        return lambda.Compile()(source);
    }